#define _USE_MATH_DEFINES
#include  <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include <stdlib.h>
#include<stdio.h>
#include <queue>
#include<map>
#include <fstream>
#include <sstream>
#include<set>
#include<stack>
#include<time.h>
#include <sys/types.h>
#include <tuple>
#include <numeric>
#include <iterator>

typedef long long int ll;
//#include<bits/stdc++.h>


using namespace std;





int main()
{

    int Q;
    Q = 1;
    //cin >> Q;


    while (Q--) {
        int k;
        cin >> k;
        int a[6] = { 2,3,5,7,11,13 };
        int b[6] = { 4,6,8,9,10,12 };
        double ans = 0;
        for (int i = 0; i < 6; i++) {
            for (int j = 0; j < 6; j++) {
                if (a[i] * b[j] == k)ans++;
            }
        }
        cout << setprecision(20);
        cout << ans / 36;

    }
    return 0;
}