Ksusha is a beginner coder. Today she starts studying arrays. She has array *a*<sub class="lower-index">1</sub>, *a*<sub class="lower-index">2</sub>, ..., *a*<sub class="lower-index">*n*</sub>, consisting of *n* positive integers.

Her university teacher gave her a task. Find such number in the array, that all array elements are divisible by it. Help her and find the number!
The first line contains integer *n* (1 ≤ *n* ≤ 10<sup class="upper-index">5</sup>), showing how many numbers the array has. The next line contains integers *a*<sub class="lower-index">1</sub>, *a*<sub class="lower-index">2</sub>, ..., *a*<sub class="lower-index">*n*</sub> (1 ≤ *a*<sub class="lower-index">*i*</sub> ≤ 10<sup class="upper-index">9</sup>) — the array elements.
n=int(input())
a=[int(x) for x in input().split()]
def check(a,num):
	for i in a:
		if i%num!=0:
			return False
	return True
start=1
end=max(a)
while start<=end:
	mid=(start+end)//2
	if check(a,mid):
		break
	elif mid>=end//2:
		end=mid-1
if mid in a:
	print(mid)
else:
	print(-1)