#define _CRT_SECURE_NO_WARNINGS
#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#include <stack>
#include <array>
#include <fstream>
#include <deque>

#define REP(i,n) for(int (i) = 0;(i) < (n) ; ++(i))
#define REPA(a,i,n) for(int (i) = (a) ; (i) < (n) ; ++(i))
#if defined(_MSC_VER)||__cplusplus > 199711L
#define AUTO(r,v) auto r = (v)
#else
#define AUTO(r,v) typeof(v) r = (v)
#endif
#define ALL(c) (c).begin() , (c).end()
#define EACH(it,c) for(AUTO(it,(c).begin());it != (c).end();++it)
#define LL long long
#define int LL
#define INF  99999999
#define DEV 1000000007
#define QUICK_CIN ios::sync_with_stdio(false); cin.tie(0);

template<class T>
bool valid(T x, T w){ return 0 <= x&&x < w; }

int di[4] = { 1, -1, 0, 0 };
int dj[4] = { 0, 0, 1, -1 };

using namespace std;

//-----------------------------------------------------------------------------------------------
//-----------------------------------------------------------------------------------------------
//-----------------------------------------------------------------------------------------------
//-----------------------------------------------------------------------------------------------

int K;

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

signed main()
{
	QUICK_CIN;
	//ifstream cin("debug.txt");
	//ofstream cout("result.txt");

	cin >> K;

	double num = 0;

	REP(i, 6){
		if (!(K%a[i])){
			int c = K / a[i];
			REP(j, 6){
				if (b[j] == c){
					num++;
				}
			}
		}
	}

	printf("%.13lf\n", num / 36.0);

	return 0;
}