#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];
	ll ans = 1;
	rep(i, N) ans = ans * a[i] % 9;
	if(ans == 0) ans = 9;
	cout << ans << endl;
}