#include"bits/stdc++.h"
using namespace std;


int main() {
	int K;
	cin >> K;
	vector<int> prime(6), composite(6);
	prime = { 2,3,5,7,11,13 };
	composite = { 4,6,8,9,10,12 };

	double cnt=0;
	for (int i = 0; i < prime.size(); i++) {
		for (int j = 0; j < composite.size(); j++) {
			if (prime[i] * composite[j] == K) {
				cnt++;
			}
		}
	}

	printf("%.15f\n", cnt/36);
}