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

double fact(int n) {
    double f = 1;
    for (int k = 2; k <= n; k++)
        f *= k;
    return f;
}

int main() {
    double P = 1;

    for (int i = 2; i <= 5; i++) {
        P *= pow(1 - 1.0 / fact(i), 2);
    }

    cout << "P = " << P << endl;
    return 0;
}