#include <iostream>

using lint = long long;

void solve() {
    lint ans = 1;

    int n;
    std::cin >> n;
    while (n--) {
        lint p;
        std::cin >> p;

        if (p == 0) {
            std::cout << 0 << std::endl;
            return;
        }

        (ans *= p % 9) %= 9;
    }

    std::cout << (ans == 0 ? 9 : ans) << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}