#include <iostream>
#include <algorithm>
#include <string>
#include <cstdio>
using namespace std;

int main()
{
    const int N = 6;
    int k, n[210] = {};
    cin >> k;

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

    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            n[a[i] * b[j]]++;
        }
    }

    printf("%.12f\n", n[k] / 36.0);

    return 0;
}