#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main() {
	int n, i, j, n1;
	double a, sum, k;
	scanf("%lf %d", &a, &n);
	n1 = n;
	k = a;
	if (n == 0) {
		sum = 1.0;
	}
	else {
		sum = 1.0 + a;
	}
	for (i = 1; i <= n; i++) {
		for (j = 1; j < n1; j++) {
			k *= a;
			if (j == n1 - 1) {
				sum += k;
				n1--;
				k = a;
			}
		}
	}
	printf("%.2lf", sum);
	return 0;
}