#include <bits/stdc++.h>
using namespace std;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
#endif
using ll = long long;
using ld = long double;
const ll INF = 1ll<<60;
const ld EPS = 1.0/1e9;
#define endl "\n"
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define fore(i,a) for(auto &i:a)
#define all(x) (x).begin(),(x).end()
#define del(x) sort(all(x)); x.erase(unique(all(x)),x.end());

int main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int a[]={2,3,5,7,11,13};
  int b[]={4,6,8,9,10,12};
  ll k; cin >> k;
  ll cnt=0;
  rep(i,0,6) rep(j,0,6) if(a[i]*b[j]==k) cnt++;
  cout << fixed << setprecision(15) << cnt/36.0 << endl;;
}