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 gcd(a,b):
	a,b=max(a,b),min(a,b)
	while True:
		if a%b==0:
			return b
		b=a%b
		a=b
if n==1:
	print(a[0])
	exit(0)
ans=max(a)
for i in range(1,n):
	if gcd(a[i],a[i-1])<=ans:
		ans=gcd(a[i],a[i-1])
	if ans==1:
		break
if ans in a:
	print(ans)
else:
	print(-1)