n = int(input())
p = list(map(int, input().split()))

if any(num == 0 for num in p):
    print(0)
else:
    product_mod9 = 1
    for num in p:
        mod = num % 9
        product_mod9 = (product_mod9 * mod) % 9
    print(9 if product_mod9 == 0 else product_mod9)