N=int(input())
xs=list(map(int,input().split()))
a=1
for x in xs:
    if x%9 != 0:
        a*= (x%9) #数字根の性質で Nの数字根 = N%9の数字根
    else:
        a*= 9

a = str(a)
while len(a)>1:
    a = sum([int(a0) for a0 in list(a)])
    a = str(a)

if int(a)%9 == 0:
    print(0)
else:
    print(a)