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

int main() {
    constexpr long double dice = (1.0 / 36.0);
    int k;
    cin >> k;
    
    long double ans = 0;
    for (const int &a : {2, 3, 5, 7, 11, 13}) {
        for (const int &b : {4, 6, 8, 9, 10, 12}) {
            if (a * b == k) ans += dice;
        }
    }
    
    cout << fixed << setprecision(20) << ans << '\n';
    return 0;
}