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())
mm = map(int, input().split())

def nsort(mass):
    d = {}
    minn = min(mass)
    maxx = max(mass)
    ans = []
    for i in range(minn, maxx + 1):
        d[i] = 0
    for elem in mass:
        d[elem] += 1
    for elem in d:
        ans += [elem] * d[elem]
    return ans

mm = nsort(mm)
d = [0]
for i in range(n):
    if mm[i] % d != 0:
        print(-1)
        break
else: print(d)