#define _CRT_SECURE_NO_WARNINGS

	#include <iostream>
	using namespace std;

	int main() {
		setlocale(LC_ALL, "Russian");
		int n;
		float a;
		scanf("%f %d", &a, &n);

		float s = 0;
		for (int j = 1; j <= n; j++) {
			float c = 1;
			for (int i = 0; i < j; i++) {
				c = c * a;
			}
			s = s + c;
		}
		printf("%f", s);

		return 0;
	}