文件目录

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

int main()
{
    int n;
    cin >> n;
    double s = 0;
    int j = 1;
    for (int i = 1; i <= n; i++)
    {
        s += j * 1.0 / i;
        j *= -1;
    }
    cout << fixed << setprecision(4) << s;
    return 0;
}