我要验牌

#include<bits/stdc++.h>
using namespace std;
int main(){
int r,ans;
string num;
cin >> r >> num;
for(int i = num.size()-1,j = 1;i >= 0;i--,j *= r){
ans += (num[i]-'0') * j;
}
cout << ans;
return 0;
}