#include <bits/stdc++.h>
#define endl '\n'
using namespace std;
typedef pair<int,int> aII;  
using ll = long long;
using ULL = unsigned long long;
const int N = 1e6+5;

ll m;
string n;
inline void solve() { 
    cin >> n >> m;
    ll res = 0;
    for (auto &i: n) {
        res = res * m + (isdigit(i)? i - '0' : i - 'A' + 10);
    }
    cout << res << endl;
}
int main() { 
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int _ = 1; 
    //int _; cin >> _;
    while (_--) solve();
    return 0;
}