from sys import stdin
import math
mod = 10**9+7

N = int(input())

A = list(map(int,stdin.readline().split()))

now = 1

for i in A:

    if i > 10 or now > 10**9+7:
        print (10**9+7)
        sys.exit()

    now *= i ** math.factorial(i)

ans = mod % now
if ans == 0:
    print (-1)
else:
    print (ans)