#include <iostream>
using namespace std;
int main(){
	int N;
	cin >> N;
	int ans = 1;
	for (int i = 0; i < N; i++){
		long long P;
		cin >> P;
		if (P == 0){
			cout << 0 << endl;
			return 0;
		}
		ans *= P % 9;
		ans %= 9;
	}
	if (ans == 0){
		ans = 9;
	}
	cout << ans << endl;
}