import math
import sys
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int, sys.stdin.readline().rstrip().split())
def LI(): return list(map(int, sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

n = I()
p = LI()

ans = 1
def f(n):
    res = 0
    for s in str(n):
        res += int(s)
        if res >= 10:
            res -= 9
    return res

for i in p:
    ans *= f(i)
    ans = f(ans)

print(ans)