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

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