Yash has recently learnt about the Fibonacci sequence and is very excited about it. He calls a sequence Fibonacci-ish if 

  1. the sequence consists of at least two elements 
  2. f0 and f1 are arbitrary 
  3. fn + 2 = fn + 1 + fn for all n ≥ 0. 



You are given some sequence of integers a1, a2, ..., an. Your task is rearrange elements of this sequence in such a way that its longest possible prefix is Fibonacci-ish sequence.

Input

The first line of the input contains a single integer n (2 ≤ n ≤ 1000) — the length of the sequence ai.

The second line contains n integers a1, a2, ..., an (|ai| ≤ 109).

Output

Print the length of the longest possible Fibonacci-ish prefix of the given sequence after rearrangement.

Examples

Input

3
1 2 -1


Output

3


Input

5
28 35 7 14 21


Output

4

Note

In the first sample, if we rearrange elements of the sequence as  - 1, 2, 1, the whole sequence ai would be Fibonacci-ish.

In the second sample, the optimal way to rearrange elements is <image>, <image>, <image>, <image>, 28.


"""
[int(i) for i in raw_input().split(" ")]
raw_input()
raw_input().split(" ")


"""

from collections import defaultdict

def fib(f1,f2,H):
	D = defaultdict(int)
	count = 2
	D[f1] += 1
	D[f2] += 1
	
	if D[f1] > H[f1]:
		return 1
	if D[f2] > H[f2]:
		return 1
	
	while True:
		f2,f1 = f1,f1+f2
		D[f1] += 1
		if D[f1] <= H[f1]:
			count += 1
		else:
			return count
	
def main():
	n = int(raw_input())
	L = [int(i) for i in raw_input().split(" ")]
	H = defaultdict(int)
	for i in L:
		H[i] += 1
	
	if len(L) == 2:
		print 2
		return
	maxi = 2
	
	tested = {}
	
	for i in range(len(L)):
		for j in range(len(L)):

			if (L[i],L[j]) in tested:
				continue
			maxi = max(maxi,fib(L[i],L[j],H))
			
			tested[(L[i],L[j])] = True
			
	print maxi
	
	
	
	
	
	
	
	
	
	
	
	
	
main()
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	