from math import gcd as g n = int(input().strip())

a = list(map(int, input().rstrip().split()))

if len(a) == 1: print(a[0] + 1) else:**

pre = [0] * len(a)
suf = [0] * len(a)

for i in range(len(a)):
    if i == 0:
        pre[i] = a[i]
    else:
        pre[i] = g(pre[i - 1], a[i])

for i in range(len(a)-1, -1, -1):
    if i == len(a) - 1:
        suf[i] = a[i]
    else:
        suf[i] = g(suf[i + 1], a[i])

final_prefix = []

for i in range(len(a)):
    if i == 0:
        final_prefix.append(suf[i + 1])
    elif i == len(a) - 1:
        final_prefix.append(pre[i - 1])
    else:
        final_prefix.append(g(pre[i - 1], suf[i + 1]))

net = {}

for i in final_prefix:
    if i in net:
        net[i] += 1
    else:
        net[i] = 1

for i in net:
    if net[i] == 1:
        ans = i
        break

print(ans)