import math
N = int(input()); MOD = pow(10,9)+7
A = list(map(int,input().split()))
if 0 in A:
  print(-1);exit()
if min(A) >= 4:
  print(MOD);exit()
ans = 1
for x in A:
  kata = math.factorial(x)
  temp = pow(x,kata)
  ans = ans*temp
print(MOD%ans)