文件目录

#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
    int n;
    long long ss = 1;
    double e = 1;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        ss *= i;
        e += 1.0 / ss;
    }
    cout << fixed << setprecision(10) << e;
    return 0;
}