#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <iomanip>
#include <cmath>
#include <functional>
using namespace std;
#define diff(x,y) ((x > y) ? (x - y) : (y - x))
#define us(x) (x > 0) ? x : x * -1
#define lli long long int

int main() {
	long double ans = 0, k;
	vector <int> s(6), g(6);
	s = { 2, 3, 5, 7, 11, 13 };
	g = { 4, 6, 8, 9, 10, 12 };
	cin >> k;
	for (int i = 0; i < 6; i++) {
		for (int j = 0; j < 6; j++) {
			if (s[i] * g[j] == k)	ans++;
		}
	}
	cout << fixed << setprecision(15) << ans / 36 << endl;
	return 0;
}