#define _USE_MATH_DEFINES	//M_PI(π),M_SQRT2(√2)
#include <iostream>			//std::cout, std::cin
#include <string>			//std::string,std::to_string(C++11)
#include <vector>			//std::vector
#include <valarray>			//std::valarray
#include <algorithm>		//std::sort
#include <time.h>			//localtime_s
#include <cstdlib>			//abs
#include <cmath>			//abs,std::pow,sqrt,sin,cos,round,floor,ceil
#include <fstream>			//std::ifstream
#include <iomanip>			//std::setprecision,std::setw,std::setfill
#include <random>			//std::random(C++11)
#include <numeric>			//std::accumulate

int main(void) {

	//test用
	//std::ifstream in("test.txt");
	//std::cin.rdbuf(in.rdbuf());

	//const unsigned int MODULO = 1000000007;	//MODULO 10^9+7用

	int K;
	std::cin >> K;

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

	double hit = 0;
	for (int i = 0; i < 6; i++) {
		for (int j = 0; j < 6; j++) {
			if (prime[i] * compo[j] == K) {
				hit++;
			}
		}
	}

	std::cout << std::fixed << std::setprecision(15) << hit / 36.0 << std::endl;

}