N = int(input())
P = list(map(int,input().split()))

ans = 1
for p in P:
  if p == 0:
    print(0)
    exit()
  if p%9 == 0:
    ans *= 9
    continue
  ans *= p%9
if ans%9 == 0:
  print(9)
else:
  print(ans%9)