题解 | #牛牛的绩点#

table = {"A":4.0,"B":3.0,"C":2.0,"D":1.0,"F":0}
score = 0  			#学分*绩点的总和
class_score = 0 		#每门课的绩点
i = 0 				#总学分
while True :
    level = input()
    if level == "False" :
        break
    elif level in table :
        class_score = table[level]
    else :
        score += int(level)*class_score
        i += int(level)
print(f'{score/i:.2f}')