#include <bits/stdc++.h>
#define rep(i, ss, ee) for (int i = ss; i < ee; ++i)
using namespace std;

double solve(int K) {
  if (K > 13 * 12) return 0;
  vector<int> p{2, 3, 5, 7, 11, 13};
  vector<int> q{4, 6, 8, 9, 10, 12};
  vector<int> r(201, 0);
  rep(i, 0, 6) {
    rep(j, 0, 6) { r[p[i] * q[j]]++; }
  }
  return (double)(r[K] / 36.0);
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int K;
  cin >> K;
  printf("%.15lf",solve(K));
  getchar();
}