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

int main() {
    int n, ans = 1;
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
        int64_t p;
        scanf("%ld", &p);
        if (p == 0) {
            puts("0");
            return 0;
        }
        (ans *= p % 9) %= 9;
    }
    if (ans == 0) ans = 9;
    printf("%d\n", ans);
}