#include <iostream>
using namespace std;

int main() {
	int prime[] = {2,3,5,7,11,};
	int composite[] = {4,6,8,9,10};
	int K;
	cin >> K;
	int count = 0;
	for (int i = 0; i < 6; i++) {
		for (int j = 0; j < 6; j++) {
			if (prime[i] * composite[j] == K) {
				count++;
			}
		}
	}
	double ans = ((double)count) / 36.0;
	cout << ans;

}