#include <bits/stdc++.h>

using namespace std;

int main() {
    int K;
    cin >> K;

    int dice1[] = {2, 3, 5, 7, 11, 13};
    int dice2[] = {4, 6, 8, 9, 10, 12};

    int cnt = 0;
    for (int i : dice1) {
        for (int j : dice2) {
            if (i * j == K) cnt++;
        }
    }

    cout << fixed << setprecision(13);
    cout << (double) cnt / 36.0 << endl;
    return 0;
}