题解 | #牛牛的绩点#
牛牛的绩点
https://www.nowcoder.com/practice/de8bc3e736164786b07a4dd64ed172f7
c = {"A": 4.0, "B": 3.0, "C": 2.0, "D": 1.0, "F": 0}
d = []
e = []
while True:
a = input()
if a == "False":
break
num = int(input())
d.append(num)
e.append(c[a] * num)
print("%.2f" % (sum(e) / sum(d)))