def main(n,a):
  mod=10**9+7
  if max(a)>=4:return mod
  if min(a)==0:return -1
  ary=[1,1]
  for i in range(2,max(a)+1):
    ary.append(ary[-1]*i)
  ret=1
  for x in a:
    ret*=pow(x,ary[x])
    if ret>mod:return mod
  return mod%ret
if __name__=='__main__':
  n=int(input())
  a=list(map(int,input().split()))
  print(main(n,a))