#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define ll long long
#define rep(i,n) for (int i = 0; i < (n); i++)
#define coutf(f) cout << fixed << setprecision(f)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()

int main() {
	int k;
	cin >> k;
	vector<int> a = { 2,3,5,7,11,13 };
	vector<int> b = { 4,6,8,9,10,12 };
	int ans = 0;
	rep(i, 6) {
		rep(j, 6) {
			if (a[i] * b[j] == k) {
				ans++;
			}
		}
	}
	coutf(10) << (double)ans / (double)36 << endl;
	return 0;
}