Problem: There are n distinct points on a coordinate line, the coordinate of i-th point equals to x_i. Choose a subset of the given set of points such that the distance between each pair of points in a subset is an integral power of two. It is necessary to consider each pair of points, not only adjacent. Note that any subset containing one element satisfies the condition above. Among all these subsets, choose a subset with maximum possible size.

In other words, you have to choose the maximum possible number of points x_{i_1}, x_{i_2}, ..., x_{i_m} such that for each pair x_{i_j}, x_{i_k} it is true that |x_{i_j} - x_{i_k}| = 2^d where d is some non-negative integer number (not necessarily the same for each pair of points).

Input

The first line contains one integer n (1 ≤ n ≤ 2 ⋅ 10^5) — the number of points.

The second line contains n pairwise distinct integers x_1, x_2, ..., x_n (-10^9 ≤ x_i ≤ 10^9) — the coordinates of points.

Output

In the first line print m — the maximum possible number of points in a subset that satisfies the conditions described above.

In the second line print m integers — the coordinates of points in the subset you have chosen.

If there are multiple answers, print any of them.

Examples

Input

6
3 5 4 7 10 12


Output

3
7 3 5

Input

5
-1 2 5 8 11


Output

1
8

Note

In the first example the answer is [7, 3, 5]. Note, that |7-3|=4=2^2, |7-5|=2=2^1 and |3-5|=2=2^1. You can't find a subset having more points satisfying the required property.

Solution (in JAVA):

Solution:
//Author: Patel Rag
//Java version "1.8.0_211"
import java.util.*;
import java.io.*;

public class Main
{
  static class FastReader
  {
    BufferedReader br;
    StringTokenizer st;

    public FastReader(){ br = new BufferedReader(new InputStreamReader(System.in)); }

    String next()
    {
      while (st == null || !st.hasMoreElements())
      {
        try
        {
          st = new StringTokenizer(br.readLine());
        }
        catch (IOException  e)
        {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    }

    int nextInt() { return Integer.parseInt(next()); }

    long nextLong(){ return Long.parseLong(next()); }

    double nextDouble(){ return Double.parseDouble(next()); }

    float nextFloat() { return Float.parseFloat(next()); }

    boolean nextBoolean() { return Boolean.parseBoolean(next()); }

    String nextLine()
    {
      String str = "";
      try
      {
        str = br.readLine();
      }
      catch (IOException e)
      {
        e.printStackTrace();
      }
      return str;
    }
  }
  static long modExp(long x, long n, long mod)    //binary Modular exponentiation
  {
    long result = 1;
    while(n > 0)
    {
        if(n % 2 == 1)
            result = (result%mod * x%mod)%mod;
        x = (x%mod * x%mod)%mod;
        n=n/2;
    }
    return result;
  }
  static long gcd(long a, long b)
  {
    if(a==0) return b;
    return gcd(b%a,a);
  }
  public static void main(String[] args)
  throws IOException
  {
    FastReader fr = new FastReader();
    int n = fr.nextInt();
    int[] dat = new int[n];
    for(int i = 0; i < n; i++) dat[i] = fr.nextInt();
    Arrays.parallelSort(dat);
    Vector<Integer> res = new Vector<>(3);
    for(int i = 0; i < n; i++)
    {
      for(int j = 0; j <= 30; j++)
      {
        int l = dat[i] - (1 << j);
        int r = dat[i] + (1 << j);
        int lf = Arrays.binarySearch(dat,l);
        int rf = Arrays.binarySearch(dat,r);
        if(lf >= 0 && rf >= 0 && res.size() < 3)
        {
          res.clear();
          res.add(l);
          res.add(dat[i]);
          res.add(r);
          System.out.println(3);
          System.out.println(res.get(0) + " " + res.get(1) + " " + res.get(2));
          return;
        }
        else if(lf >= 0 && res.isEmpty())
        {
          res.add(l);
          res.add(dat[i]);
        }
        else if(rf >=0 && res.isEmpty())
        {
          res.add(dat[i]);
          res.add(r);
        }
      }
    }
    if(!res.isEmpty())
    {
      System.out.println(2);
      System.out.println(res.get(0) + " " + res.get(1));
    }
    else
    {
      System.out.println(1);
      System.out.println(dat[0]);
    }


  }
}
class pair
{
  public int first;
  public int second;
  public pair(int first,int second)
  {
    this.first = first;
    this.second = second;
  }
  public int first() { return first; }
  public int second() { return second; }
  public void setFirst(int first) { this.first = first; }
  public void setSecond(int second) { this.second = second; }
}
class myComp implements Comparator<pair>
{
  public int compare(pair a,pair b)
  {
    return (a.first - b.first);
  }
}

class BIT       //Binary Indexed Tree aka Fenwick Tree
{
  public long[] m_array;

  public BIT(long[] dat)
  {
    m_array = new long[dat.length + 1];
    Arrays.fill(m_array,0);
    for(int i = 0; i < dat.length; i++)
    {
      m_array[i + 1] = dat[i];
    }
    for(int i = 1; i < m_array.length; i++)
    {
      int j = i + (i & -i);
      if(j < m_array.length)
      {
        m_array[j] = m_array[j] + m_array[i];
      }
    }
  }

  public final long prefix_query(int i)
  {
    long result = 0;
    for(++i; i > 0; i = i - (i & -i))
    {
      result = result + m_array[i];
    }
    return result;
  }

  public final long range_query(int fro, int to)
  {
    if(fro == 0)
    {
      return prefix_query(to);
    }
    else
    {
      return (prefix_query(to) - prefix_query(fro - 1));
    }
  }

  public void update(int i, long add)
  {
    for(++i; i < m_array.length; i = i + (i & -i))
    {
      m_array[i] = m_array[i] + add;
    }
  }
}