#include <iostream>

#include <cmath>
//#include <math.h>


using namespace std;

const int N = 15;

int main() {

    double stirling{0};
    long normal{0};

    stirling = exp(-N) * pow(N,N) * sqrt(2*M_PI *N);
    normal = 15l*14l*13l*12*11*10*9*8*7*6*5*4*3*2;

    cout << N << "! by stirlings is " << stirling << endl;
    cout << N << "! by computation is " << normal << endl;

    return 0;
}