import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

N,*A = map(int,read().split())

x = 1
for a in A:
    x *= a; x %= 9

if x == 0:
    x = 9
if any(a == 0 for a in A):
    x = 0
print(x)