#include <iostream>
#include <iomanip>
#include <math.h>

using namespace std;

int main() {
	int n,k;
	cin >> n >> k;

	double n_double = (double)n;

	double expectation = 0.f;
	for( int i = 0; i < k; i++ ) {
		double p_less = std::floor(expectation)/n_double;
		expectation = p_less * expectation 
					+ (double(1.f) - p_less) * (std::max(double(1.), std::ceil(expectation)) + n_double) / double(2.f);
	}

	std::cout << setprecision(10) << expectation << std::endl;
}