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