CF299A.Ksusha and Array

Ksusha is a beginner coder. Today she starts studying arrays. She has array _a_1, _a_2, ..., a__n, 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!

库舒莎是一名编程新手。今天她开始学习数组。她有一个由 $n$ 个正整数组成的数组 $a_1, a_2, \dots, a_n$。

她的大学老师给她布置了一项任务：在该数组中找出一个数，使得数组中的所有元素都能被它整除。请帮她找出这个数！

The first line contains integer n (1 ≤ n ≤ 105), showing how many numbers the array has. The next line contains integers _a_1, _a_2, ..., a__n (1 ≤ a__i ≤ 109) — the array elements.

第一行包含一个整数 $n$（$1 \leq n \leq 10^5$），表示数组中数字的个数。
下一行包含整数 $a_1, a_2, ..., a_n$（$1 \leq a_i \leq 10^9$）—— 数组的元素。

Print a single integer — the number from the array, such that all array elements are divisible by it. If such number doesn't exist, print -1.

If there are multiple answers, you are allowed to print any of them.

输出一个整数——即数组中的某个数，使得数组中所有元素都能被它整除。如果不存在这样的数，则输出 $-1$。

如果存在多个满足条件的答案，你可以输出其中任意一个。