#include<bits/stdc++.h>
using namespace std;

int main(){
	cin.tie(0),ios::sync_with_stdio(false);
	vector<int>p={2,3,5,7,11,13},m={4,6,8,9,10,12};
	int k; cin>>k;
	int n=0;
	for(int i=0;i<6;++i){
		for(int j=0;j<6;++j){
			if(p.at(i)*m.at(j)==k)++n;
		}
	}
	cout<<fixed<<setprecision(20)<<(long double)n/36<<"\n"s;
}