mod = 10**9+7
N = int(input())
A = list(map(int, input().split()))
if 0 in A:
  print(-1)
  exit()
ans = 1
for i in range(N):
  prod = A[i]
  for j in range(A[i],0,-1):
    prod = pow(prod,j)
    if ans*prod>mod:
      print(mod)
      exit()
  ans *= prod
ans = mod%ans
if ans==0:
  print(-1)
else:
  print(ans)