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.
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
 
public class Main {
	public static void main(String[] args) throws NumberFormatException,
	IOException {Solve solve = new Solve();solve.solve();}
}
class Solve{
	void dump(int[]a){for(int i=0;i<a.length;i++)System.out.print(a[i]+" ");System.out.println();}
	void dump(int[]a,int n){for(int i=0;i<a.length;i++)System.out.printf("%"+n+"d",a[i]);System.out.println();}
	void dump(long[]a){for(int i=0;i<a.length;i++)System.out.print(a[i]+" ");System.out.println();}
	void dump(char[]a){for(int i=0;i<a.length;i++)System.out.print(a[i]);System.out.println();}
	String itob(int a,int l){return String.format("%"+l+"s",Integer.toBinaryString(a)).replace(' ','0');}
	void solve() throws NumberFormatException, IOException{
		final ContestScanner in = new ContestScanner();
		Writer out = new Writer();
		int n = in.nextInt();
		int[] a = new int[n];
		int z = 0;
		MultiSet<Integer> set = new MultiSet<>();
		for(int i=0; i<n; i++){
			a[i] = in.nextInt();
			set.add(a[i]);
			if(a[i] == 0) z++;
		}
		int max = z;
		int[] use = new int[100];
		for(int ai: set.keySet()){
			for(int aj: set.keySet()){
				if(ai==0 && aj==0) continue;
				use[0] = ai;
				set.add(ai, -1);
				if(set.get(aj)<1){
					set.add(ai);
					continue;
				}
				use[1] = aj;
				set.add(aj, -1);
				int cnt = 2;
				int a1 = ai;
				int a2 = aj;
				while(set.get(a1+a2)>0){
					int tmp = a1;
					a1 = a2;
					a2 += tmp;
					set.add(a2, -1);
					use[cnt] = a2;
					cnt++;
				}
				for(int k=0; k<cnt; k++){
					set.add(use[k]);
				}
				max = Math.max(max, cnt);
			}
		}
		System.out.println(max);
	}
}

class MultiSet<T> extends HashMap<T, Integer>{
	@Override
	public Integer get(Object key){return containsKey(key)?super.get(key):0;}
	public void add(T key,int v){put(key,get(key)+v);}
	public void add(T key){put(key,get(key)+1);}
	public void sub(T key)
	{final int v=get(key);if(v==1)remove(key);else put(key,v-1);}
}
class Timer{
	long time;
	public void set(){time=System.currentTimeMillis();}
	public long stop(){return time=System.currentTimeMillis()-time;}
	public void print()
	{System.out.println("Time: "+(System.currentTimeMillis()-time)+"ms");}
	@Override public String toString(){return"Time: "+time+"ms";}
}
class Writer extends PrintWriter{
	public Writer(String filename)throws IOException
	{super(new BufferedWriter(new FileWriter(filename)));}
	public Writer()throws IOException{super(System.out);}
}
class ContestScanner {
	private InputStreamReader in;private int c=-2;
	public ContestScanner()throws IOException 
	{in=new InputStreamReader(System.in);}
	public ContestScanner(String filename)throws IOException
	{in=new InputStreamReader(new FileInputStream(filename));}
	public String nextToken()throws IOException {
		StringBuilder sb=new StringBuilder();
		while((c=in.read())!=-1&&Character.isWhitespace(c));
		while(c!=-1&&!Character.isWhitespace(c)){sb.append((char)c);c=in.read();}
		return sb.toString();
	}
	public String readLine()throws IOException{
		StringBuilder sb=new StringBuilder();if(c==-2)c=in.read();
		while(c!=-1&&c!='\n'&&c!='\r'){sb.append((char)c);c=in.read();}
		return sb.toString();
	}
	public long nextLong()throws IOException,NumberFormatException
	{return Long.parseLong(nextToken());}
	public int nextInt()throws NumberFormatException,IOException
	{return(int)nextLong();}
	public double nextDouble()throws NumberFormatException,IOException 
	{return Double.parseDouble(nextToken());}
}