题解 | #牛牛的绩点#
牛牛的绩点
https://www.nowcoder.com/practice/de8bc3e736164786b07a4dd64ed172f7
grade = {'A':4, 'B':3, 'C':2, 'D':1, 'F':0}
score = 0
xuefen = 0
while (gpa := input()) != 'False' :
xf = int(input())
score += grade[gpa] * xf
xuefen += xf
print(r'%.2f' % (score/xuefen))