# coding: utf-8
# Your code here!
import sys
sys.setrecursionlimit(10**6)
readline = sys.stdin.readline
 
#h,w,k = [int(i) for i in readline().split()]
#n = int(input())
#ab = [[int(i) for i in readline().split()] for _ in range(n)]


n = int(input())
a = [int(i) for i in readline().split()]


ans = 1
ok = 1
for i in a:
    ans *= i
    ans %= 9
    if not i: ok = 0

if ok:
    print(ans if ans != 0 else 9)
else:
    print(0)