<?php

$rules = preg_split('/\n/', trim(file_get_contents("input.txt")));

$containers = [];
$i = 0;

foreach( $rules as $rule )
{
	preg_match('/([\w ]+) bags contain (.*?)\./', $rule, $matches);
	$contained_list = preg_split('/, /', $matches[2]);
	
	$containers[$i] =[];
	$containers[$i]['name'] = $matches[1];
	
	$all_contained = [];
		
	foreach ( $contained_list as $contained_item )
	{
		$contained_item = preg_replace('/ bags?$/', '', $contained_item);
		preg_match('/^(\d+) (.*?)$/', $contained_item, $matches);
		
		$count = $matches[1];
		$contained_color = $matches[2];
						
		$all_contained[] = [ 'count' => $count, 'color' => $contained_color ];
		$containers[$i]['contents'] = $all_contained;		
	}
	
	++$i;
}

$target_color = 'shiny gold';

$possible_containers = [];
$highest_count = 0;

foreach ( $containers as $container )
{
	foreach ( $container['contents'] as $content )
	{
		if ( $content['color'] == $target_color )
		{
			$possible_containers[] = $container;
			break;
		}
	}
}

for ( ;; )
{
	$top_level_containers = $possible_containers;
	
	foreach ( $top_level_containers as $top_level_container )
	{
		$target_color = $top_level_container['name'];
	
		foreach ( $containers as $container )
		{
			if ( in_array($container, $possible_containers) )
			{
				continue;
			}
			
			foreach ( $container['contents'] as $content )
			{
				if ( $content['color'] == $target_color )
				{
					$possible_containers[] = $container;
					break;
				}
			}
		}
	}
	
	if ( count($possible_containers) > $highest_count )
	{
		$highest_count = count($possible_containers);
	}
	else
	{
		break;
	}

	print count($possible_containers) . "\n";
}