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 functools
def gcd(a, b):
    if b == 0:
        return a;
    return gcd(b, a % b)

def main():
    n = int(input())
    a = [int(x) for x in input().split()]
    ans = functools.reduce(gcd, a);
    if ans == 1 and 1  not in a:
        print(-1)
    else:
        print(ans)

if __name__ == '__main__':
    main()
