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

int main()
{
    int k;
    cin >> k;
    double p = 0;
    int a[] = {2, 3, 5, 7, 11, 13};
    int b[] = {4, 6, 8, 9, 10, 12};
    for (int i = 0; i < 6; i++)
    {
        for (int j = 0; j < 6; j++)
        {
            if (a[i] * b[j] == k)
                p += 1;
        }
    }
    cout << setprecision(20) << p / 36 << endl;
}