#include <bits/stdc++.h>
using namespace std;

typedef signed long long ll;
typedef long double ld;

#define rep(i,n) for(int i = 0; i < (n); i++)
#define all(x) x.begin(),x.end()

#define DEBUG

int main()
{
	double d;
	cin >> d;
	cout << 1/d << endl;
	return 0;
}