#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <climits>
#include <iomanip>
#include <set>
#include <map>
using namespace std;
typedef long long ll;
int main(){
    ll n;
    cin >> n;
    vector<ll> a = {2,3,5,7,11,13};
    vector<ll> b = {4,6,8,9,10,12};
    double k = 0;
    for(int i = 0;i < 6;i++){
        for(int j = 0;j < 6;j++){
            if(a[i] * b[j] == n)k++;
          //cout << a[i] << " " << b[j] << endl;
        }
    }
    double res = (double)(k / 36);
    cout << fixed << setprecision(20) << res << endl;
}