Problem:
Score : 300 points

Problem Statement

There are N integers, A_1, A_2, ..., A_N, written on the blackboard.

You will choose one of them and replace it with an integer of your choice between 1 and 10^9 (inclusive), possibly the same as the integer originally written.

Find the maximum possible greatest common divisor of the N integers on the blackboard after your move.

Constraints

All values in input are integers.

2 \leq N \leq 10^5

1 \leq A_i \leq 10^9

Output

Input is given from Standard Input in the following format:

N
A_1 A_2 ... A_N

Output

Print the maximum possible greatest common divisor of the N integers on the blackboard after your move.

Sample Input 1

3
7 6 8

Sample Output 1

2

If we replace 7 with 4, the greatest common divisor of the three integers on the blackboard will be 2, which is the maximum possible value.

Sample Input 2

3
12 15 18

Sample Output 2

6

Sample Input 3

2
1000000000 1000000000

Sample Output 3

1000000000

We can replace an integer with itself.

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

N = int(input())
# スペース区切りの整数の入力
A = list(map(int, input().split()))


def gcd(a, b):
  while b > 0:
    a, b = b, a%b
  return a

ans=[]

if N==2:
  sol=max(A[0],A[1])

else:
  for i in range(3):
    B=A[:]
    del B[i]
    sol=0
    for b in B:
        sol=gcd(sol,b)
    ans.append(sol)
    sol=max(ans)


print(sol)