hahahahahahahahahaha

#include <iostream>
#include <cmath>
using namespace std;
int main(){
    unsigned long long sum = 0;
    int p;
    string cnt;
    cin >> p >> cnt;
    int len = cnt.length();
    for(int i = len - 1; i >= 0; i--){
        if(cnt[i] >= 'A' and cnt[i] <= 'F'){
            sum += (cnt[i] - 'A' + 10) * pow(p, len - i - 1);
        }else{
            sum += (cnt[i] - '0') * pow(p, len - i - 1);
        }
    }
    cout << sum;
    return 0;
}