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.
#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:102400000,102400000")
using namespace std;
const int block_size = 360;
const int maxn = 100010;
const long long mod = 1e9 + 7;
const long double eps = 1e-9;
template <typename T>
int sign(const T& a) {
  if (a < 0) {
    return -1;
  }
  if (a > 0) {
    return 1;
  }
  return 0;
}
long long cross_product(const complex<long long>& from, complex<long long> a,
                        complex<long long> b) {
  a -= from;
  b -= from;
  return a.imag() * b.real() - a.real() - b.imag();
}
long long shuzu[1000];
map<long long, int> app;
set<pair<long long, long long> > appear;
int main() {
  int n;
  scanf("%d", &n);
  for (long long i = 0; i < n; i++) {
    scanf("%lld", &shuzu[i]);
    app[shuzu[i]]++;
  }
  int ans = 2;
  for (long long i = 0; i < n; i++) {
    for (long long j = 0; j < n; j++) {
      if (i == j) {
        continue;
      }
      if (shuzu[i] == shuzu[j] && shuzu[i] == 0) {
        ans = max(ans, app[0]);
      } else {
        map<long long, int> temp;
        temp[shuzu[i]] = 1;
        temp[shuzu[j]] = 1;
        if (appear.find(make_pair(shuzu[i], shuzu[j])) != appear.end()) {
          continue;
        } else {
          appear.insert(make_pair(shuzu[i], shuzu[j]));
        }
        long long a = shuzu[i], b = shuzu[j];
        int temp_ans = 2;
        while (app[a + b] - temp[a + b] > 0) {
          temp[a + b]++;
          swap(a, b);
          b = a + b;
          temp_ans++;
        }
        ans = max(ans, temp_ans);
      }
    }
  }
  cout << ans << endl;
  return 0;
}
