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>
using namespace std;
const long long linf = 1e18 + 5;
const int mod = (int)1e9 + 7;
const int logN = 17;
const int inf = 1e9;
const int N = 2e5 + 5;
int n, a[N], b, c, t;
vector<int> v[1001][1001];
int h[N];
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
  }
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++) {
      int ind = lower_bound(a + 1, a + n + 1, a[i] + a[j]) - a;
      if (a[ind] == a[i] + a[j]) {
        v[i][j].push_back(ind++);
      }
      if (ind <= n && a[ind] == a[i] + a[j]) {
        v[i][j].push_back(ind++);
      }
      if (ind <= n && a[ind] == a[i] + a[j]) {
        v[i][j].push_back(ind);
      }
      if (ind <= n && a[ind] == a[i] + a[j]) {
        v[i][j].push_back(ind);
      }
    }
  int cur = 0, res = 0;
  for (int i = 1; i <= n; i++) res += (a[i] == 0);
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++) {
      if (a[i] == 0 && a[j] == 0) continue;
      if (i == j) continue;
      vector<int> temp;
      temp.push_back(i);
      temp.push_back(j);
      h[i] = h[j] = 1;
      int ans = 2;
      int l1 = i, l2 = j;
      while (1) {
        if (!v[l1][l2].size()) break;
        int tt = l2;
        if (!h[v[l1][l2][0]]) {
          temp.push_back(v[l1][l2][0]);
          h[l2 = v[l1][l2][0]] = 1;
        } else if (v[l1][l2].size() > 1 && !h[v[l1][l2][1]]) {
          temp.push_back(v[l1][l2][1]);
          h[l2 = v[l1][l2][1]] = 1;
        } else if (v[l1][l2].size() > 2 && !h[v[l1][l2][2]]) {
          temp.push_back(v[l1][l2][2]);
          h[l2 = v[l1][l2][2]] = 1;
        } else if (v[l1][l2].size() > 3 && !h[v[l1][l2][3]]) {
          temp.push_back(v[l1][l2][3]);
          h[l2 = v[l1][l2][3]] = 1;
        } else
          break;
        ans++;
        l1 = tt;
      }
      for (__typeof(temp.begin()) it = temp.begin(); it != temp.end(); it++)
        h[*it] = 0;
      res = max(res, ans);
    }
  cout << res << '\n';
  return 0;
}
