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:
//package contests.CF988;

import java.io.*;
import java.util.HashMap;
import java.util.HashSet;
import java.util.StringTokenizer;

public class D {

    static HashSet<Long> set;
    public static void main(String[] args) throws IOException {
        Scanner sc = new Scanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);

        int n = sc.nextInt();

        set = new HashSet<>();
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
            set.add(1l*arr[i]);
        }

        int[] ans = new int[3];
        int num = 1;
        ans[0] = arr[0];

        out: for (int pt = 0; pt < arr.length; pt++) {
            for (int i = 0; (1l << i) <= 2000_000_000 ; i++) {
                int pow = 1 << i;
                if(get((long)arr[pt]+pow) && get((long)arr[pt]-pow))
                {
                    num = 3;
                    ans[0] = arr[pt]+pow;
                    ans[1] = arr[pt];
                    ans[2] = arr[pt]-pow;
                    break out;
                }

                if(get((long)arr[pt]+pow))
                {
                    num = 2;
                    ans[0] = arr[pt];
                    ans[1] = arr[pt]+pow;
                    continue out;
                }
                if(get((long)arr[pt]-pow))
                {
                    num = 2;
                    ans[0] = arr[pt];
                    ans[1] = arr[pt]-pow;
                    continue out;
                }
            }
        }

        pw.println(num);
        for (int i = 0; i < num; i++) {
            pw.print(ans[i] + " ");
        }

        pw.flush();
        pw.close();
    }

    static boolean get(long a){
        return set.contains(a);
    }
    static class Scanner
    {
        StringTokenizer st; BufferedReader br;
        public Scanner(InputStream s){	br = new BufferedReader(new InputStreamReader(s));}
        public Scanner(String s) throws FileNotFoundException {	br = new BufferedReader(new FileReader(new File(s)));}
        public String next() throws IOException {while (st == null || !st.hasMoreTokens()) st = new StringTokenizer(br.readLine());return st.nextToken();}
        public int nextInt() throws IOException {return Integer.parseInt(next());}
        public long nextLong() throws IOException {return Long.parseLong(next());}
        public String nextLine() throws IOException {return br.readLine();}
        public boolean ready() throws IOException {return br.ready();}
    }
}