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

int main() {
  vector<int> S(6), G(6), SG;
  S = {2, 3, 5, 7, 11, 13};
  G = {4, 6, 8, 9, 10, 12};
  for (int i = 0; i < 6; i++)
    for (int j = 0; j < 6; j++)
      SG.push_back(S.at(i) * G.at(j));

  int K;
  cin >> K;  
  double cnt = 0;
  for (int i = 0; i < SG.size(); i++) if (SG.at(i) == K) cnt++;

  cout << fixed << setprecision(12) << cnt / 36;
}