#include <iostream>
#include <iomanip>
using namespace std;
int main() {
	int prime[6] = { 2,3,5,7,11,13 };
	int K,count = 0;
	cin >> K;
	for (int i = 0; i < 6;i++) {
		if (K%prime[i] == 0) {
			int k = K / prime[i];
			if ((k % 2 == 0 && k / 2 > 1 && k / 2 < 7) || k == 9) {
				count++;
			}
		}
	}
	cout << fixed << setprecision(12) << (count / 36.0) << endl;
	return 0;
}