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.

n = int(input())
l = [int(x) for x in raw_input().split()]

def fibonacci_ish(n,seq):
    if n <= 2:
        return n

    dictionary = {}
    for x in seq:
        if dictionary.has_key(x):
            dictionary[x] += 1
        else:
            dictionary[x] = 1
    startPairs = {}
    ma = max(seq)
    mi = min(seq)
    result = 2
    for i in range(n):
        for j in range(n):
            if i == j:
                continue
            f0 = seq[i]
            f1 = seq[j]

            if startPairs.has_key((f0,f1)) or f0 + f1 > ma or f0 + f1 < mi:
                continue
            startPairs[(f0,f1)] = True           
            tempResult = 2            
            dictCopy = {}
            if f0 == f1 :
                dictCopy[f0] = 2
            else:
                dictCopy[f0] = 1
                dictCopy[f1] = 1
            #print (f0, f1, dictCopy, i, j)
            
            while dictionary.has_key(f0 + f1):
                f2 = f0 + f1
                if not dictCopy.has_key(f2):
                    dictCopy[f2] = 1
                elif dictCopy.has_key(f2) and dictCopy[f2] == dictionary[f2]:
                    break;
                else:
                    dictCopy[f2] += 1
                
                tempResult += 1
                f0 = f1
                f1 = f2

            result = max(result,tempResult)

    return result
                
                
print fibonacci_ish(n,l)                   
    
