include <iostream>

include <cmath>

using namespace std;

define ll long long

int main () { double n, m = 0; cin >> n; for (double i = 1; i <= n; i++) { m += (1 / (i * (i + 1))); } cout.precision (6); cout << m; }

//This Code Is Made By Ayxan113

include <iostream>

include <cmath>

using namespace std; int main () { double n, m = 0; cin >> n; for (double i = 1; i <= n; i++) { m += (1 / (i * (i + 1))); } cout.precision (6); cout << m; }//NAHID ZEYD VE RESADDAN PROOOOOO!!!!!!!!!!!