// log.Printf("%d bags could be tucked in a %q", solveSecond(data), myBag)

	log.Printf("%d bags could be tucked in a %q", solveSecond(data, myBag), myBag)

func solveSecond(data Container, root string) int {
	var sum int
	for _, c := range data[root] {
		sum += c.piece + c.piece*solveSecond(data, c.kind)
	}
	return sum
}