#include <bits/stdc++.h>
#include "bits/stdc++.h"
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cmath>
#include <stack>
#include <queue>
#include <cctype>
#include <stdio.h>
#include <map>
#include <unordered_map>
#include <string.h>
#include <utility>

typedef long long ll;
const int INF = 1e8;

#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
using namespace std;

typedef pair<int, int> P;

int a[] ={2,3,5,7,11,13};
int b[] ={4,6,8,9,10,12};

int main() {

	int n=0;
	cin>>n;

	int ct=0;
	for(int i=0; i<6; i++){
		for(int j=0; j<6; j++){
			if(a[i]*b[j] ==n){
				ct++;
			}
		}
	}

	if(ct==0){
		cout<<fixed<<setprecision(18)<<0.0<<endl;
	}else {
		cout<<fixed<<setprecision(18)<<1/pow(6,ct*2)<<endl;
	}




	return 0;
}