#include <iostream>
#include <iomanip>
#include <vector>
using namespace std;
int main(void) {
	int k;
	cin >> k;
	vector<int> 
		product(201, 0),
		prime_dice = { 2,3,5,7,11,13 },
		composite_dice = { 4,6,8,9,10,12 };
	for (int i = 0; i < 6; ++i) {
		for (int j = 0; j < 6; ++j) {
			++product[prime_dice[i] * composite_dice[j]];
		}
	}
	double ans = 0;
	if (product[k] != 0) {
		ans = product[k] / 36.0;
	}
	cout << fixed << setprecision(20) << ans << endl;
	return 0;
}