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.
def gcd(a, b):
	factor = a
	while b%factor != 0:
		temp = factor
		factor = b%factor
		b = temp
	return(factor)

def main():
	n = int(input())
	arr = list(map(int, input().split(" ")))

	if n == 1:
		print(arr[0])
		return
	factor = gcd(arr[0], arr[1])
	found = 1 if factor in (arr[0], arr[1]) else 0
	# print(factor, found)
	count = 2
	while count < n:
		if factor != 1:
			cd = gcd(factor, arr[count])
			if cd != factor and cd != arr[count]:
				found = 0
			else:
				found = 1
			factor = cd
		else:
			if arr[count] == 1:
				found = 1
				break
		count += 1
		# print(factor, found)

	if found:
		print(factor)
	else:
		print(-1)


if __name__ == "__main__":
	main()

