#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint1000000007;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000000000

int main(){	
	
	vector<long long> p = {2,3,5,7,11,13};
	vector<long long> c = {4,6,8,9,10,12};
	
	double ans = 0.0;
	long long k;
	cin>>k;
	
	rep(i,6){
		rep(j,6){
			if(p[i]*c[j]==k)ans += 1.0 / 36.0;
		}
	}
	cout<<fixed<<setprecision(15)<<ans<<endl;
	
	return 0;
	
}