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

using ll = long long;
#define rep(i, n) for(int i = 0; i < n; i++)

int main() {
	int N;
	cin >> N;
	vector<ll> a(N);
	rep(i, N) cin >> a[i];
	if(N == 1 && a[0] < 10) {
		cout << a[0] % 9 << endl;
		return 0;
	}
	ll ans = 1, z = 0;
	rep(i, N) {
		if(a[i] == 0) z = 1;
		if(a[i]) ans = ans * a[i] % 9;
	}
	if(ans == 0 && z == 0) ans = 9;
	cout << ans << endl;
}