#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <limits.h>
#include <vector>
#include <numeric>
#include <iomanip>
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;
	float ans = 0;
	float test = 27777777777777;
	
	cin >> k;
	for(int iy=0; iy<6; iy++){
		for(int ix=0; ix<6; ix++){
			if(sosuu[iy] * gousei[ix] == k){
				cnt += 1;
			}
		}
	}
	
	if(cnt == 0){
		cout << "0.00000000000000000" << endl;
	}else if(cnt == 1){
		cout << "0.0277777777777777778" << endl;
	}else if(cnt == 2){
		cout << "0.0555555555555555555" << endl;
	}else if(cnt == 3){
		cout << "0.0833333333333333333" << endl;
	}else if(cnt == 4){
		cout << "0.1111111111111111111" << endl;
	}

	
	
	return 0;
}