#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <fstream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

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

int main() {
	int K; cin >> K;
	int cnt = 0;
	for (int i = 0; i < 6; i++)
		for (int j = 0; j < 6; j++)
			if (a[i] * b[j] == K)
				cnt++;
	printf("%.15f\n", cnt / 36.0);
}