#include <iostream>
#include <vector>
#include <cmath>
  
using namespace std;


int main() {

    int n;
    double x;

    cin >> n >> x;

    double sum = 0;
    double f = 1;

    for (int i = 0; i <= n; ++i) {
        if (i & 1) {
            sum -= pow(x, i * 2) / f;
        } else {
            sum += pow(x, i * 2) / f;
        }
        f *= (i + 1);
        f *= (i + 2);
    }

    cout << "Cos(x) = " << sum;

    return 0;
}