#include <iostream>
#include <iomanip>

using namespace std;

double fact(int n) {
    double x = 1;

    for (int i = 1; i <= n; ++i) {
        x *= i;
    }

    return x / (n + 1);
}

int main()
{
    double sum=0;

    for (int i = 1; i <= 10; ++i) {
        sum += fact(i);
    }

    cout << setprecision(3*10) << sum << endl;

    return 0;
}