NB!!

66666

错误代码

Python:

m,x=map(int,input().split())
s=input()[::-1]

for i in range(len(s)):
    if s[i]!='M':
        continue
    else:
        s=s[i:]
        break
flag = 0
for i in range(len(s)):
    if s[i] == 'M':
        flag += m
    else:
        flag += int(s[i]) * x
print(flag)