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

int main() {
    int N;
    cin >> N;
    ll P[N];
    for (int i = 0; i < N; i++) {
        cin >> P[i];
    }
    ll k = P[0] % 9;
    for (int i = 1; i < N; i++) {
        if (k == 0) {
            cout << "9\n";
            return 0;
        }
        k *= P[i];
        k %= 9;
    }
    cout << k << "\n";
    return 0;
}