#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <iomanip>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
using namespace std;
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
#define LONGINF 1000000000000000000
double hoge[2000] = {};
int main() {
	int k;
	cin >> k;
	int cnt[6] = { 2,3,5,7,11,13 };
	int h[6] = { 4,6,8,9,10,12 };
	double wow = 1;
	wow /= 36;
	for (int i = 0;i < 6;++i) {
		REP(q, 6) {
			hoge[cnt[i] * h[q]] += wow;
		}
	}
	cout <<setprecision(20) <<  hoge[k] << endl;
	return 0;
}