#include <stdio.h>

int main(void)
{
    int a, n, i;
    int sum = 0;
    int x;

scanf("%d %d", &a, &n);
x = 1;

 for (i = 0; i < n; i++)
{
x *= a;
sum += x;
}
    printf("%d\n", sum);
return 0;
}