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

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

int main() {
    double S = 0;

    for (int i = 0; i <= 10; i++) {
        S += pow(-1, i + 1) / fact(i * i);
    }

    cout << fixed << setprecision(6);
    cout << "S = " << S << endl;
    return 0;
}