#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rep1(i, n) for(int i = 1; i <= (n); i++)
#define co(x) cout << (x) << "\n"
#define cosp(x) cout << (x) << " "
#define ce(x) cerr << (x) << "\n"
#define cesp(x) cerr << (x) << " "
#define pb push_back
#define mp make_pair
#define Would
#define you
#define please

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);


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

	map<int, int> MP;
	rep(i, 6) rep(j, 6) {
		MP[A[i] * B[j]]++;
	}

	int K;
	cin >> K;
	int kazu = MP[K];
	double kotae = kazu * 1.0 / 36;

	cout << fixed << setprecision(14) << kotae << endl;



	Would you please return 0;
}