#include <bits/stdc++.h>
using namespace std;
int main(){
  cout << fixed << setprecision(20);
  int K;
  cin >> K;
  vector<int> A = {2, 3, 5, 7, 11, 13};
  vector<int> B = {4, 6, 8, 9, 10, 12};
  int cnt = 0;
  for (int i = 0; i < 6; i++){
    for (int j = 0; j < 6; j++){
      if (A[i] * B[j] == K){
        cnt++;
      }
    }
  }
  cout << (double) cnt / 36 << endl;
}