#include <iostream>
#include <vector>
#include "conio.h"

using namespace std;

int main()
{
    char c;
    int k, y;
    double d = 0;
    bool OK = false;
    int n = 0;
    cin >> n;

    c = char(0);
    while (c != char(13))
    {
        OK = false;
        c = getch();
        cout << c;
        if ((c >= '0') && (c <= '9'))
        {
            y = int (c) - int ('0');
            OK = true;
        }
        else
            if ((c >= 'a') && (c <= 'z'))
            {
                OK = true;
                y = (int)c - 87;
            }
        if (OK) d = d * n + y;
    }
    cout << endl;
    cout << d;
    return 0;
}