#include <bits/stdc++.h>
#define int long long
using namespace std;
using Graph = vector<vector<int>>;

signed main(){
  
  vector<int> sosu(6);
  vector<int> gose(6);
  sosu = {2,3,5,7,11,13};
  gose = {4,6,8,9,10,12};
  
  vector<int> seki;
  for( int i = 0; i < 6; i++ ){
    for( int j = 0; j < 6; j++ ) seki.push_back(sosu.at(i)*gose.at(j));
  }
  
  int K;
  cin >> K;
  
  int kazu = 0;
  for( int i = 0; i < seki.size(); i++ ){
    if( seki.at(i) == K ) kazu++;
  }
  
  cout << fixed << setprecision(15);
  double ans = (double)kazu/36.0;
  cout << ans << endl;
  
}