#include <iostream>
#include <list>
#include <vector>
#include <string>
#include <stdio.h>
#include <stdint.h>
using namespace std;

using uint = unsigned int;
using ll = long long;

#define CIN( LL , A ) LL A; cin >> A 
#define GETLINE( A ) string A; getline( cin , A ) 

#include <iomanip>

int main()
{

  CIN( ll , K );
  const ll P[6] = { 2 , 3 , 5 , 7 , 11 , 13 };
  const ll C[6] = { 4 , 6 , 8 , 9 , 10 , 12 };
  ll num = 0;
  
  for( ll i = 0 ; i < 36 ; i++ ){

    if( K == P[i/6] * C[i%6] ){

      num++;

    }
    
  }

  double p = num / 36.0;
  cout << setprecision( 13 ) << p << endl;
  return 0;

}