#include <iostream>
#include <set>
using namespace std;

int n;
string s;

int main(int argc, char *argv[]){
	cin >> s;
	n = (s.size() < 3) ? atoi(s.c_str()) : 50;
	int ans = set<int>({9, 10, 15, 16, 22}).count(n) ? 7 :
			  set<int>({10, 18}).count(n) ? 8 :
			  set<int>({15, 16}).count(n) ? 13 :
			  set<int>({21, 22}).count(n) ? 19 : 
			  24 < n ? 8 : n-1;
	cout << ans << endl;
	return 0;
}