N=int(input())
A=list(map(int,input().split()))
F=[1,1,2,6]
P=1
for i in range(N):
  if A[i]>3:
    print(10**9+7)
    exit()
  P*=pow(A[i],F[A[i]])
  if P>10**9+7:
    print(10**9+7)
    exit()
if P==0:
  print(-1)
  exit()
print((10**9+7)%P)