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 int N = 40;
void solve() {
  int n;
  cin >> n;
  unordered_set<int> st;
  set<int> pr;
  unordered_map<int, int> col;
  int ans = 0;
  for (int i = 0; i < n; i++) {
    int x;
    cin >> x;
    if (col.find(x) == col.end()) {
      col[x] = 0;
    }
    col[x]++;
    if (x == 0) {
      ans++;
    }
    pr.insert(x);
    st.insert(x);
  }
  vector<int> a;
  while (!pr.empty()) {
    a.push_back(*pr.begin());
    pr.erase(*pr.begin());
  }
  n = a.size();
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      unordered_map<int, int> col2;
      int f = a[i];
      int s = a[j];
      if (col2.find(s) == col2.end()) {
        col2[s] = 0;
      }
      if (col2.find(f) == col2.end()) {
        col2[f] = 0;
      }
      col2[f]++;
      col2[s]++;
      if (col[s] < col2[s]) {
        continue;
      }
      int tmp = 2;
      while (1) {
        int sm = f + s;
        if (col2.find(sm) == col2.end()) {
          col2[sm] = 0;
        }
        if (st.count(sm) == 0 || col[sm] <= col2[sm]) {
          break;
        }
        col2[sm]++;
        tmp++;
        f = s;
        s = sm;
      }
      ans = max(ans, tmp);
    }
  }
  cout << ans;
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  solve();
}
