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

struct Precision{
  Precision(){
    cout<<fixed<<setprecision(12);
  }
}precision_beet;

//INSERT ABOVE HERE
signed main(){
  Int p[]={2,3,5,7,11,13};
  Int q[]={4,6,8,9,10,12};
  Int k;
  cin>>k;
  Int cnt=0;
  for(Int i=0;i<6;i++)
    for(Int j=0;j<6;j++)
      cnt+=k==p[i]*q[j];

  cout<<cnt/36.0<<endl;
  return 0;
}