diff --git a/aoc b/aoc
index 7be3c49..dbfb0d6 100755
--- a/aoc
+++ b/aoc
@@ -4,6 +4,7 @@ require __DIR__.'/vendor/autoload.php';
 
 use NunoMaduro\Collision\Provider as CollisionProvider;
 use Symfony\Component\Console\Application;
+use trizz\AdventOfCode\Commands\AddDay;
 use trizz\AdventOfCode\Commands\ExecuteDay;
 use trizz\AdventOfCode\Commands\Puzzle;
 use trizz\AdventOfCode\Commands\TestDay;
@@ -15,6 +16,7 @@ $application = new Application('Advent of Code by trizz');
 $application->add(new Puzzle());
 $application->add(new ExecuteDay());
 $application->add(new TestDay());
+$application->add(new AddDay());
 
 try {
     $application->run();
diff --git a/composer.json b/composer.json
index 8129715..2db3d64 100644
--- a/composer.json
+++ b/composer.json
@@ -13,6 +13,8 @@
         "php": "^8.3",
         "ext-mbstring": "*",
         "cebe/markdown": "^1.2",
+        "laravel/prompts": "^0.1.13",
+        "nette/php-generator": "^4.1",
         "phppkg/cli-markdown": "^2.0",
         "symfony/console": "^6"
     },
diff --git a/composer.lock b/composer.lock
index 12d5c72..e8d0ce5 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "fca53f959d62471b393002b4f61d1351",
+    "content-hash": "bd86bd7f56cbbfba41f30bc5a5a27b50",
     "packages": [
         {
             "name": "cebe/markdown",
@@ -70,6 +70,413 @@
             },
             "time": "2018-03-26T11:24:36+00:00"
         },
+        {
+            "name": "illuminate/collections",
+            "version": "v10.34.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/collections.git",
+                "reference": "8e4c4f97ea066cd6aec962ef8a6abc09dfd5e754"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/collections/zipball/8e4c4f97ea066cd6aec962ef8a6abc09dfd5e754",
+                "reference": "8e4c4f97ea066cd6aec962ef8a6abc09dfd5e754",
+                "shasum": ""
+            },
+            "require": {
+                "illuminate/conditionable": "^10.0",
+                "illuminate/contracts": "^10.0",
+                "illuminate/macroable": "^10.0",
+                "php": "^8.1"
+            },
+            "suggest": {
+                "symfony/var-dumper": "Required to use the dump method (^6.2)."
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "10.x-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "helpers.php"
+                ],
+                "psr-4": {
+                    "Illuminate\\Support\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Collections package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2023-11-27T14:46:52+00:00"
+        },
+        {
+            "name": "illuminate/conditionable",
+            "version": "v10.34.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/conditionable.git",
+                "reference": "d0958e4741fc9d6f516a552060fd1b829a85e009"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/conditionable/zipball/d0958e4741fc9d6f516a552060fd1b829a85e009",
+                "reference": "d0958e4741fc9d6f516a552060fd1b829a85e009",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^8.0.2"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "10.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Illuminate\\Support\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Conditionable package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2023-02-03T08:06:17+00:00"
+        },
+        {
+            "name": "illuminate/contracts",
+            "version": "v10.34.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/contracts.git",
+                "reference": "f6bf37a272fda164f6c451407c99f820eb1eb95b"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/contracts/zipball/f6bf37a272fda164f6c451407c99f820eb1eb95b",
+                "reference": "f6bf37a272fda164f6c451407c99f820eb1eb95b",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^8.1",
+                "psr/container": "^1.1.1|^2.0.1",
+                "psr/simple-cache": "^1.0|^2.0|^3.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "10.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Illuminate\\Contracts\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Contracts package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2023-10-30T00:59:22+00:00"
+        },
+        {
+            "name": "illuminate/macroable",
+            "version": "v10.34.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/macroable.git",
+                "reference": "dff667a46ac37b634dcf68909d9d41e94dc97c27"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/macroable/zipball/dff667a46ac37b634dcf68909d9d41e94dc97c27",
+                "reference": "dff667a46ac37b634dcf68909d9d41e94dc97c27",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^8.1"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "10.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Illuminate\\Support\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Macroable package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2023-06-05T12:46:42+00:00"
+        },
+        {
+            "name": "laravel/prompts",
+            "version": "v0.1.13",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/laravel/prompts.git",
+                "reference": "e1379d8ead15edd6cc4369c22274345982edc95a"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/laravel/prompts/zipball/e1379d8ead15edd6cc4369c22274345982edc95a",
+                "reference": "e1379d8ead15edd6cc4369c22274345982edc95a",
+                "shasum": ""
+            },
+            "require": {
+                "ext-mbstring": "*",
+                "illuminate/collections": "^10.0|^11.0",
+                "php": "^8.1",
+                "symfony/console": "^6.2|^7.0"
+            },
+            "conflict": {
+                "illuminate/console": ">=10.17.0 <10.25.0",
+                "laravel/framework": ">=10.17.0 <10.25.0"
+            },
+            "require-dev": {
+                "mockery/mockery": "^1.5",
+                "pestphp/pest": "^2.3",
+                "phpstan/phpstan": "^1.10",
+                "phpstan/phpstan-mockery": "^1.1"
+            },
+            "suggest": {
+                "ext-pcntl": "Required for the spinner to be animated."
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-main": "0.1.x-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "src/helpers.php"
+                ],
+                "psr-4": {
+                    "Laravel\\Prompts\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "support": {
+                "issues": "https://github.com/laravel/prompts/issues",
+                "source": "https://github.com/laravel/prompts/tree/v0.1.13"
+            },
+            "time": "2023-10-27T13:53:59+00:00"
+        },
+        {
+            "name": "nette/php-generator",
+            "version": "v4.1.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nette/php-generator.git",
+                "reference": "abc0e79b2d02d4b8aba5933765b90df3f610c143"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nette/php-generator/zipball/abc0e79b2d02d4b8aba5933765b90df3f610c143",
+                "reference": "abc0e79b2d02d4b8aba5933765b90df3f610c143",
+                "shasum": ""
+            },
+            "require": {
+                "nette/utils": "^3.2.9 || ^4.0",
+                "php": "8.0 - 8.3"
+            },
+            "require-dev": {
+                "jetbrains/phpstorm-attributes": "dev-master",
+                "nette/tester": "^2.4",
+                "nikic/php-parser": "^4.15",
+                "phpstan/phpstan": "^1.0",
+                "tracy/tracy": "^2.8"
+            },
+            "suggest": {
+                "nikic/php-parser": "to use ClassType::from(withBodies: true) & ClassType::fromCode()"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "4.1-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause",
+                "GPL-2.0-only",
+                "GPL-3.0-only"
+            ],
+            "authors": [
+                {
+                    "name": "David Grudl",
+                    "homepage": "https://davidgrudl.com"
+                },
+                {
+                    "name": "Nette Community",
+                    "homepage": "https://nette.org/contributors"
+                }
+            ],
+            "description": "🐘 Nette PHP Generator: generates neat PHP code for you. Supports new PHP 8.3 features.",
+            "homepage": "https://nette.org",
+            "keywords": [
+                "code",
+                "nette",
+                "php",
+                "scaffolding"
+            ],
+            "support": {
+                "issues": "https://github.com/nette/php-generator/issues",
+                "source": "https://github.com/nette/php-generator/tree/v4.1.2"
+            },
+            "time": "2023-10-29T22:57:32+00:00"
+        },
+        {
+            "name": "nette/utils",
+            "version": "v4.0.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nette/utils.git",
+                "reference": "a9d127dd6a203ce6d255b2e2db49759f7506e015"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nette/utils/zipball/a9d127dd6a203ce6d255b2e2db49759f7506e015",
+                "reference": "a9d127dd6a203ce6d255b2e2db49759f7506e015",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.0 <8.4"
+            },
+            "conflict": {
+                "nette/finder": "<3",
+                "nette/schema": "<1.2.2"
+            },
+            "require-dev": {
+                "jetbrains/phpstorm-attributes": "dev-master",
+                "nette/tester": "^2.5",
+                "phpstan/phpstan": "^1.0",
+                "tracy/tracy": "^2.9"
+            },
+            "suggest": {
+                "ext-gd": "to use Image",
+                "ext-iconv": "to use Strings::webalize(), toAscii(), chr() and reverse()",
+                "ext-intl": "to use Strings::webalize(), toAscii(), normalize() and compare()",
+                "ext-json": "to use Nette\\Utils\\Json",
+                "ext-mbstring": "to use Strings::lower() etc...",
+                "ext-tokenizer": "to use Nette\\Utils\\Reflection::getUseStatements()"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "4.0-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause",
+                "GPL-2.0-only",
+                "GPL-3.0-only"
+            ],
+            "authors": [
+                {
+                    "name": "David Grudl",
+                    "homepage": "https://davidgrudl.com"
+                },
+                {
+                    "name": "Nette Community",
+                    "homepage": "https://nette.org/contributors"
+                }
+            ],
+            "description": "🛠  Nette Utils: lightweight utilities for string & array manipulation, image handling, safe JSON encoding/decoding, validation, slug or strong password generating etc.",
+            "homepage": "https://nette.org",
+            "keywords": [
+                "array",
+                "core",
+                "datetime",
+                "images",
+                "json",
+                "nette",
+                "paginator",
+                "password",
+                "slugify",
+                "string",
+                "unicode",
+                "utf-8",
+                "utility",
+                "validation"
+            ],
+            "support": {
+                "issues": "https://github.com/nette/utils/issues",
+                "source": "https://github.com/nette/utils/tree/v4.0.3"
+            },
+            "time": "2023-10-29T21:02:13+00:00"
+        },
         {
             "name": "phppkg/cli-markdown",
             "version": "v2.0.2",
@@ -167,6 +574,57 @@
             },
             "time": "2021-11-05T16:47:00+00:00"
         },
+        {
+            "name": "psr/simple-cache",
+            "version": "3.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/simple-cache.git",
+                "reference": "764e0b3939f5ca87cb904f570ef9be2d78a07865"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/simple-cache/zipball/764e0b3939f5ca87cb904f570ef9be2d78a07865",
+                "reference": "764e0b3939f5ca87cb904f570ef9be2d78a07865",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.0.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\SimpleCache\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interfaces for simple caching",
+            "keywords": [
+                "cache",
+                "caching",
+                "psr",
+                "psr-16",
+                "simple-cache"
+            ],
+            "support": {
+                "source": "https://github.com/php-fig/simple-cache/tree/3.0.0"
+            },
+            "time": "2021-10-29T13:26:27+00:00"
+        },
         {
             "name": "symfony/console",
             "version": "v6.4.1",
diff --git a/src/Commands/AddDay.php b/src/Commands/AddDay.php
new file mode 100644
index 0000000..f658671
--- /dev/null
+++ b/src/Commands/AddDay.php
@@ -0,0 +1,150 @@
+<?php
+
+namespace trizz\AdventOfCode\Commands;
+
+use Nette\PhpGenerator\ClassType;
+use Nette\PhpGenerator\PhpNamespace;
+use Nette\PhpGenerator\Printer;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use trizz\AdventOfCode\Solution;
+
+use function Laravel\Prompts\text;
+
+final class AddDay extends Command
+{
+    #[\Override]
+    protected function configure(): void
+    {
+        $this
+            ->setName('add:day')
+            ->setDescription('Add a new day.')
+            ->addArgument('day', InputArgument::OPTIONAL, 'The day number.')
+            ->addArgument('year', InputArgument::OPTIONAL, 'The year', date('y'));
+    }
+
+    #[\Override]
+    protected function execute(InputInterface $input, OutputInterface $output): int
+    {
+        $day = $input->getArgument('day');
+        $year = $input->getArgument('year');
+
+        if ($day === null) {
+            $day = text(
+                label: 'For which day?',
+                placeholder: '3',
+                default: date('j'),
+                required: true,
+                validate: fn ($value) => is_numeric($value) && $value > 0 && $value < 26 ? null : 'Please enter a valid day number.'
+            );
+        }
+
+        $example1Result = text(
+            label: 'Please enter the result for example 1.',
+            required: true,
+            validate: fn ($value) => is_numeric($value) ? null : 'Please enter a valid number.'
+        );
+
+        // Create short year.
+        $year = strlen($year) === 4 ? substr($year, 2) : $year;
+
+        $output->writeln("Adding files for day {$day} of year '{$year}.");
+
+        $this
+            ->createDirs($year, $day)
+            ->createClass($day, $year, $example1Result)
+            ->addExampleDirs($year, $day);
+
+        return Command::SUCCESS;
+    }
+
+    protected function createDirs(int $year, int $day): self
+    {
+        if (!is_dir($dir = "src/Y{$year}") && !mkdir($dir) && !is_dir($dir)) {
+            throw new \RuntimeException(sprintf('Directory "%s" was not created', $dir));
+        }
+
+        if (!is_dir($dir = "data/Y{$year}/day{$day}") && !mkdir($dir) && !is_dir($dir)) {
+            throw new \RuntimeException(sprintf('Directory "%s" was not created', $dir));
+        }
+
+        return $this;
+    }
+
+    protected function createClass(string $day, string $year, string $example1Result): self
+    {
+        $namespace = new PhpNamespace('trizz\AdventOfCode\Y'.$year);
+        $class = new ClassType('Day'.$day);
+
+        $class->setFinal()
+            ->setExtends(Solution::class);
+
+        $this->createClassProperties($class, $example1Result);
+        $this->createClassMethods($class);
+
+        $namespace->add($class);
+        $this->printClassToFile($class, $year, $day, $namespace);
+
+        return $this;
+    }
+
+    private function createClassProperties(ClassType $class, string $example1Result): void
+    {
+        $properties = [
+            'part1ExampleResult' => $example1Result,
+            'part1Result' => null,
+            'part2ExampleResult' => null,
+            'part2Result' => null,
+        ];
+
+        foreach ($properties as $name => $value) {
+            $class
+                ->addProperty($name, $value)
+                ->setPublic()
+                ->setStatic()
+                ->setType('null|int|string');
+        }
+    }
+
+    private function createClassMethods(ClassType $class): void
+    {
+        $methods = ['part1', 'part2'];
+
+        foreach ($methods as $methodName) {
+            $class
+                ->addMethod($methodName)
+                ->setReturnType('int')
+                ->setBody('return -1;')
+                ->addParameter('data')->setType('array');
+        }
+    }
+
+    private function printClassToFile(ClassType $class, string $year, string $day, PhpNamespace $namespace): void
+    {
+        $printer = new Printer();
+        $printer->indentation = '    ';
+
+        $filename = __DIR__.'/../Y'.$year.'/Day'.$day.'.php';
+        if (file_exists($filename)) {
+            throw new \RuntimeException("File {$filename} already exists.");
+        }
+
+        file_put_contents($filename, '<?php'.PHP_EOL.$printer->printNamespace($namespace));
+    }
+
+    protected function addExampleDirs(mixed $year, mixed $day): self
+    {
+        $dataDir = __DIR__.'/../../data/Y'.$year.'/day'.$day;
+
+        if (!is_dir($dataDir) && !mkdir($dataDir) && !is_dir($dataDir)) {
+            throw new \RuntimeException(sprintf('Directory "%s" was not created', $dataDir));
+        }
+
+        touch($dataDir.'/example.txt');
+        touch($dataDir.'/data.txt');
+
+        return $this;
+    }
+}