#include <bits/stdc++.h>
#define rep(i, a, n) for (int i = a; i < n; i++)
#define repr(i, a, n) for (int i = n - 1; i >= a; i--)
using namespace std;
using ll = long long;
using P = pair<int, int>;
template <typename T> void chmin(T &a, T b) { a = min(a, b); }
template <typename T> void chmax(T &a, T b) { a = max(a, b); }

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  int k;
  cin >> k;
  int prims[6]{2, 3, 5, 7, 11, 13};
  int compos[6]{4, 6, 8, 9, 10, 12};
  double ans = 0;
  rep(i, 0, 6) {
    rep(j, 0, 6) {
      if (prims[i] * compos[j] == k)
        ans++;
    }
  }
  cout << fixed << setprecision(15) << ans / 36 << endl;
}