逐个判断就ok了

#include <bits/stdc++.h>
using namespace std;
int main(){
int n,sum=0;
char a;
cin >> n >> a;

if(n<=1000){
    if(a=='y'){
        sum+=5;
    }
    sum+=8;
}else{
    if(a=='y'){
       sum+=5;
    }
    sum+=8;
    n-=1000;
    n=n+(500-n%500);
    sum+=(n/500)*4;
}
cout << sum;
return 0;

}