#933
N = int(input())
P = list(map(int,input().split()))
ans = 1
for i in P:
    if i == 0:
        i = 0
    elif i%9 == 0:
        i = 9
    else:
        i = i%9
    ans *= i

while ans >= 10:
    tmp = 0
    for i in str(ans):
        tmp += int(i)
    ans = tmp
print(ans)