#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

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

    int k;
    cin >> k;

    double ans = 0.0;
    for(int i=0; i<6; ++i){
        for(int j=0; j<6; ++j){
            if(a[i] * b[j] == k)
                ans += 1.0 / 36.0;
        }
    }
    printf("%.15f\n", ans);

    return 0;
}