#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <complex>
#include <queue>
#include <set>
#include <unordered_map>
#include <iomanip>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)

typedef long long ll;

int main() {

  unordered_map<int, int> mp;
  int P[] = {2,3,5,7,11,13};
  int C[] = {4,6,8,9,10,12};

  rep(i, 6) rep(j, 6) {
    mp[P[i]*C[j]]++;
  }
  int K; cin >> K;
  cout << setprecision(15) << mp[K] / 36.0 << endl;

  return 0;
}