#include<stdio.h>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main() {

	int K;
	cin >> K;

	int s[6] = {2,3,5,7,11,13}, g[6] = {4,6,8,9,10,12};

	int cnt = 0;
	for (int i = 0; i < 6; i++) {
		for (int j = 0; j < 6; j++) {
			if ( (s[i]*g[j]) == K) cnt++;
		}
	}

	//printf_s("%.14f\n", (double)cnt/36.0);
	printf("%.14f\n", (double)cnt / 36.0);

	return 0;
}