#include<bits/stdc++.h>

using namespace std;
using ll=long long;
#define rep2(i, a, n) for(int i = (a); i < (n); i++)
#define rep(i, n) rep2(i,0,n)

int main(){
  cin.tie(nullptr);ios_base::sync_with_stdio(false);
  cout<<fixed<<setprecision(15);
  double cnt=0,k;cin>>k;
  int hoge[6]={2,3,5,7,11,13},shake[6]={4,6,8,9,10,12};
  for(int i:hoge){
    for(int j:shake){
      if(i*j==k)cnt++;
    }
  }
  cout<<cnt/36<<endl;
}