class Solution:
def numWaterBottles(self, numBottles: int, numExchange: int) -> int:
cnt = numBottles # 统计瓶数
while numBottles >= numExchange:
exchange = numBottles // numExchange # 能换几瓶
# 执行换操作
numBottles -= exchange * numExchange #拿去换的
numBottles += exchange #换回来的
cnt += exchange
return cnt