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 INF = 2e9 + 2;
const long long MOD = 1e9 + 7;
const int MAXN = 1e5 + 2;
long long aa[1002];
map<long long, int> cant;
long long sim[1002];
map<pair<long long, long long>, pair<long long, long long> > sgte;
map<pair<long long, long long>, int> ret;
map<int, vector<int> > tmp;
map<pair<long long, long long>, int>::iterator it2, itr;
map<pair<long long, long long>, pair<long long, long long> >::iterator it;
map<pair<long long, long long>, pair<long long, long long> >::iterator itt;
void dfs(pair<long long, long long> par, int deep,
         pair<long long, long long> last) {
  int u = par.first, v = par.second;
  if (sgte[par] == make_pair(INF, INF)) {
    tmp[v].push_back(0);
    ret[par] = 2;
  } else {
    tmp[v].push_back(deep);
    if (tmp[u].size() < cant[u]) {
      ret[par] = ret[last] + 1;
    } else {
      ret[par] = deep - tmp[u][0] + 1;
      tmp[u].erase(tmp[u].begin());
    }
  }
  if (sgte.count(make_pair(v - u, u))) dfs(make_pair(v - u, u), deep + 1, par);
}
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%I64d", &aa[i]);
  int max0 = 0;
  for (int i = 0; i < n; ++i)
    if (aa[i] == 0) ++max0;
  for (int i = 0; i < n; ++i) ++cant[aa[i]];
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < n; ++j)
      if (i != j) sgte[make_pair(aa[i], aa[j])] = make_pair(INF, INF);
  }
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < n; ++j) {
      if (aa[i] == 0 && aa[j] == 0) continue;
      if (i == j) continue;
      if (cant.count(aa[i] + aa[j])) {
        if (aa[i] == 0 && cant[aa[j]] == 1) continue;
        sgte[make_pair(aa[i], aa[j])] = make_pair(aa[j], aa[i] + aa[j]);
      }
    }
  }
  for (it = sgte.begin(); it != sgte.end(); ++it) {
    pair<long long, long long> par = it->first;
    if (par.first == 0 && par.second == 0) continue;
    if (sgte[par] == make_pair(INF, INF)) {
      dfs(par, 0, make_pair(INF, INF));
      tmp.clear();
    }
  }
  int ans = max0;
  for (itr = ret.begin(); itr != ret.end(); ++itr) {
    ans = max(ans, itr->second);
  }
  ans = min(ans, n);
  cout << ans << endl;
  return 0;
}
