#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <limits.h>
#include <vector>
#include <numeric>
using namespace std;

int main(){
	const int sosuu[6] = {2,3,5,7,11,13};
	const int gousei[6] = {4,6,8,9,10,12};
	int k;
	int cnt = 0;
	double ans;
	cin >> k;
	for(int iy=0; iy<6; iy++){
		for(int ix=0; ix<6; ix++){
			if(sosuu[iy] * gousei[ix] == k){
				cnt ++;
			}
		}
	}
	
	ans = static_cast<double>(cnt) / 36.0;
	cout << ans << endl;
	
	
	return 0;
}