#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <utility>
#include <cstring>
#include <cmath>
#include <queue>
#include <set>
#include <map>
#include <cstdio>
using namespace std;

#define rep(i,n) for(int i=0; i<n; i++)
typedef long long ll;
typedef pair<int,int> pii;

int main() {
	int p[6] = {2, 3, 5, 7, 11, 13};
	int q[6] = {4, 6, 8, 9, 10, 12};
	map<int, int> mp;
	rep(i, 6) {
		rep(j, 6) {
			mp[p[i]*q[j]]++;
		}
	}
	int k;
	cin >> k;
	printf("%.15lf\n", 1. * mp[k] / 36.0);
	return 0;
}