#include<bits/stdc++.h>
using namespace std;
int gcd(int a, int b) {
  return b != 0 ? gcd(b, a % b) : a;
}
int lcm(int a, int b) {
  return a * b / gcd(a, b);
}
 main() {
 double n;
 cin >>n;
 double ans =1/n;
 cout << ans <<endl;
 }