Q10268: 498'

// Run time: 0.120
#include <stdio.h>
#define N 500000
int arr[N];
void calculate(int x, int num);

int main()
{
    int i;
    int num;
    int x;
    while (scanf("%d", &x) != EOF)
    {
        for ( i = 0; ; i++)
        {
            scanf("%d", &arr[i]);

            if (getchar() == '\n')
                break;
        }

        num = i; // <=

        if (x)
            calculate(x, num);
        else
            printf("%d\n", arr[num-1]);


    }

    return 0;
}

void calculate(int x, int num)
{
    int i, j;
    long long int sum = 0;
    long long int product = 1;

    for ( i = num-1, j = 1; i >= 0; i--, j++)
    {
        sum += arr[i]*product*j;
        product *= x;
    }

    printf("%lld\n", sum);
}