#include <iostream>
#include <string>
#include <vector>
#include <math.h>
#include <sstream>
using namespace std;

int main()
{
    long long int x;

    while (cin >> x)
    {
        string input;
        cin.ignore();
        getline(cin, input);
        vector<long long int> a;

        stringstream ss(input);

        long long int c;

        while (ss >> c)
            a.insert(a.begin(), c);

        long long int len = (long long int)a.size();

        long long int ans = 0;

        for (long long int i = 0; i < len; i++)
            ans += i * a[i] * (long long int)round(pow(x, (i - 1)));


        cout << ans << endl;
    }

    return 0;
}