//#include <atcoder/all>
#include<bits/stdc++.h>
using namespace std;
//using namespace atcoder;
using ll = long long;
#define all(A) A.begin(),A.end()
using vll = vector<ll>;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
using Graph = vector<vector<ll>>;
vector<ll> fact, factinv, inv;


int main() {
   ll K;
   ll an=0;
   cin>>K;
   vll A={2,3,5,7,11,13};
   vll B={4,6,8,9,10,12};
   rep(i,6){
       rep(j,6){
           if(A[i]*B[j]==K)an++;
       }
   }
   cout<<setprecision(16)<<double(an)/36.0<<endl;

}