答案

#include <bits/stdc++.h>
using namespace std;
int main(){    
    char s;    
    int x;    
    cin>>s>>x;    
    double kg;    
    if(s=='A') kg=60;    
    else if(s=='B') kg=45;    
    else kg=30;    
    double total=x/1000.0*kg;    
    printf("%.2lf",total);    
    return 0;
}