#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <iomanip>
using namespace std;
using ll = long long;

int main() {
    int K;
    cin >> K;
    double res = 0;
    vector<int> dice1 = {2, 3, 5, 7, 11, 13}, dice2 = {4, 6, 8, 9, 10, 12};
    for(int i=0; i<6; ++i) {
        for(int j=0; j<6; ++j) {
            if(dice1[i]*dice2[j] == K) {
                res += 1 / 36.0;
            }
        }
    }
    cout << fixed << setprecision(15) << res << endl;
}