#include <iostream>
#include <math.h>
using namespace std;

int main() {
	int n;
	double x, p = 1;
	double cs, sc;
	cin >> x;
	cin >> n;
	cs = cos(fabs(x));
	sc = cos(fabs(x));
	for(int k = 1; k <=n; k++)
	{
		p*= (k / (k + 1)) - cs;
		cs*=sc;
	}
	cout << p << endl;
	return 0;
}