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

int main() {
  ios::sync_with_stdio(false);

  int N;
  cin >> N;

  vector<int64_t> P(N);
  for (int i = 0; i < N; ++i) {
    cin >> P[i];
  }

  bool zero = false;
  int ans = 1;
  for (int64_t p : P) {
    zero |= p == 0;
    ans = ans * (p % 9) % 9;
  }

  if (zero) cout << 0 << endl;
  else if (ans == 0) cout << 9 << endl;
  else cout << ans << endl;

  return 0;
}