#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main() {
  int n;
  cin >> n;
  vector <ll> p(n);
  for (int i = 0; i < n; i++) {
	  cin >> p[i];
	}
  ll ans   = 1;
  bool flg = true;
  for (int i = 0; i < n; i++) {
	  if (p[i] == 0) {
		  flg = false;
		}
	  ans = (ans * (p[i] % 9)) % 9;
	}
  if (flg && ans == 0) {
	  ans = 9;
	}
  cout << ans << endl;
  return 0;
}