#include<iostream>
#include<algorithm>
#include <vector>
#include<cmath>
#include<iomanip>
using namespace std;
typedef long long int lont;
int main() {
	int K;
	cin >> K;
	vector<int>veca(6);
	vector<int>vecb(6);
	veca = { 2, 3, 5, 7, 11, 13 };
	vecb = { 4, 6, 8, 9, 10, 12 };
	vector<int>vecc(36);
	int cnta = 0;
	for (int ia = 0; ia < 6; ia++) {
		for (int ib = 0; ib < 6; ib++) {
			vecc.at(cnta) = veca.at(ia) * vecb.at(ib);
			cnta++;
		}
	}
	double cntb = 0;
	for (int ic = 0; ic < 36; ic++) {
		if (vecc.at(ic) == K) {
			cntb++;
		}
	}
	cout << cntb / 36 << endl;
}