#include <bits/stdc++.h>
using namespace std;
#define int long long
#define REP(i,n) for(int i = 0;i < (int)(n);i++)
template<class T>inline bool CHMAX(T&a,T b){if(a<b){a = b;return true;}return false;}
template<class T>inline bool CHMIN(T&a,T b){if(a>b){a = b;return true;}return false;}



signed main(){
	int N;
	cin >> N;
	cout<<1.0/N<<endl;
}