import math
n = int(input())
a = list(map(int,input().split()))

if min(a) == 0:
  print(-1)
  exit()
elif max(a) >= 4:
  print(((10)**9)+7)
  exit()
else:
  ans = 1
  for i in range(n):
    tmp = math.factorial(a[i])
    ans *= a[i]**tmp
    if ans >= ((10)**9)+7:
      print((10**9)+7)
      exit()
  print(((10**9)+7)%ans)