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

int main(){
  int sosuu[6] = {2, 3, 5, 7, 11, 13};
  int gouseisuu[6] = {4, 6, 8, 9, 10, 12};
  int k;
  cin >> k;
  int count = 0;
  for(int i = 0; i < 6; i++){
    for(int j = 0; j < 6; j++){
      if(sosuu[i] * gouseisuu[j] == k){
        count++;
      }
    }
  }
  double ans = count / 36.;
  printf("%.15f\n", ans);
  return 0;
}