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.
import sys 
sys.stdout = open("C:\\code\\output.txt",'w')
sys.stdin = open("C:\\code\\input.txt",'r') 
import math
# Shortcut for input
def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))
def S(): return input()
# Constants
mod = 10**9 + 7
def main(a):
    g = 0 
    s = set()
    for i in range(len(a)):
        g = math.gcd(g,a[i])
        s.add(a[i])
    if g in s:
        return g
    else:
        return -1


n = I()
a = LI()
print(main(a))

