package q1518

func numWaterBottles(numBottles int, numExchange int) int {
	drink := 0
	empty := 0
	for {
		drink += numBottles
		empty += numBottles
		if empty < numExchange {
			break
		}

		numBottles = empty / numExchange
		empty = empty % numExchange
	}
	return drink
}

var _ = numWaterBottles