import sys
input=lambda: sys.stdin.readline().rstrip()
n=int(input())
A=[int(i) for i in input().split()]
mod=10**9+7
if max(A)>=4:
	print(mod)
elif min(A)==0:
	print(-1)
else:
	F=[1,1,2,6]
	cur=1
	for a in A:
		cur*=pow(a,F[a])
		if cur>mod:
			print(mod)
			break
	else:
		print(mod%cur)