data/advent07a.txt

   1 light red bags contain 1 bright white bag, 2 muted yellow bags.
   2 dark orange bags contain 3 bright white bags, 4 muted yellow bags.
   3 bright white bags contain 1 shiny gold bag.
   4 muted yellow bags contain 2 shiny gold bags, 9 faded blue bags.
   5 shiny gold bags contain 1 dark olive bag, 2 vibrant plum bags.
   6 dark olive bags contain 3 faded blue bags, 4 dotted black bags.
   7 vibrant plum bags contain 5 faded blue bags, 6 dotted black bags.
   8 faded blue bags contain no other bags.
   9 dotted black bags contain no other bags.