Given 2 integers u and v, find the shortest array such that [bitwise-xor](https://en.wikipedia.org/wiki/Bitwise_operation#XOR) of its elements is u, and the sum of its elements is v.

Input

The only line contains 2 integers u and v (0 ≤ u,v ≤ 10^{18}).

Output

If there's no array that satisfies the condition, print "-1". Otherwise:

The first line should contain one integer, n, representing the length of the desired array. The next line should contain n positive integers, the array itself. If there are multiple possible answers, print any.

Examples

Input


2 4


Output


2
3 1

Input


1 3


Output


3
1 1 1

Input


8 5


Output


-1

Input


0 0


Output


0

Note

In the first sample, 3⊕ 1 = 2 and 3 + 1 = 4. There is no valid array of smaller length.

Notice that in the fourth sample the array is empty.
//package Round628;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.List;

/**
 * @author sguar <shugangcao@gmail.com>
 * strive for greatness
 * Created on 2020-01-10
 */
public class D {
    InputStream is;
    PrintWriter out;
    private static final String INPUT_FILE_NAME = "/Users/sguar/IdeaProjects/kotlinLearn/src/input.txt";

    void solve() {
        debug(Double.valueOf(1e18).longValue());
        long u = nl();
        long v = nl();
        if (u > v) {
            out.println(-1);
        } else {
            long[] pow2 = new long[62];
            pow2[0] = 1;
            for (int i = 1; i < 62; i++) {
                pow2[i] = pow2[i - 1] * 2;
                debug(i, pow2[i]);
            }

            boolean[] has1 = new boolean[62];
            int[] cnt = new int[62];
            for (int i = 61; i >= 0; i--) {
                if ((u >> i) % 2 == 1) {
                    has1[i] = true;
                    cnt[i]++;
                    v -= pow2[i];
                }
            }

            for (int i = 61; i >= 0; i--) {
                if (v >= pow2[i]) {
                    long c = v / pow2[i];
                    if (c % 2 == 1) {
                        c--;
                    }
                    cnt[i] += (int) c;
                    v -= pow2[i] * c;
                }
            }
            if (v > 0) {
                out.println("-1");
            } else {

                List<Long> ans = new ArrayList<>();
                while (true) {
                    long a = 0;
                    for (int i = 0; i < 62; i++) {
                        if (cnt[i] > 0) {
                            a += pow2[i];
                            cnt[i]--;
                        }
                    }
                    if (a > 0) {
                        ans.add(a);
                    } else {
                        break;
                    }
                }
                out.println(ans.size());
                ans.forEach(a -> out.print(a + " "));
            }
        }

    }

    class Pair {
        int x;
        int y;

        Pair(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override
        public String toString() {
            return "x: " + x + ", y: " + y;
        }
    }

    public static long invl(long a, long mod) {
        long b = mod;
        long p = 1, q = 0;
        while (b > 0) {
            long c = a / b;
            long d;
            d = a;
            a = b;
            b = d % b;
            d = p;
            p = q;
            q = d - c * q;
        }
        return p < 0 ? p + mod : p;
    }


    void run() throws Exception {

        is = oj ? System.in : new FileInputStream(INPUT_FILE_NAME);
        out = new PrintWriter(System.out);

        long s = System.currentTimeMillis();
        solve();
        out.flush();
        debug(System.currentTimeMillis() - s + "ms");
    }

    public static void main(String[] args) throws Exception {
        new D().run();
    }

    private byte[] inbuf = new byte[1024];
    int lenbuf = 0;
    int ptrbuf = 0;

    private int readByte() {
        if (lenbuf == -1) throw new InputMismatchException();
        if (ptrbuf >= lenbuf) {
            ptrbuf = 0;
            try {
                lenbuf = is.read(inbuf);
            } catch (IOException e) {
                throw new InputMismatchException();
            }
            if (lenbuf <= 0) return -1;
        }
        return inbuf[ptrbuf++];
    }

    private boolean isSpaceChar(int c) {
        return !(c >= 33 && c <= 126);
    }

    private int skip() {
        int b;
        while ((b = readByte()) != -1 && isSpaceChar(b)) ;
        return b;
    }

    private double nd() {
        return Double.parseDouble(ns());
    }

    private char nc() {
        return (char) skip();
    }

    private String ns() {
        int b = skip();
        StringBuilder sb = new StringBuilder();
        while (!(isSpaceChar(b))) { // when nextLine, (isSpaceChar(b) && b != ' ')
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    private char[] ns(int n) {
        char[] buf = new char[n];
        int b = skip(), p = 0;
        while (p < n && !(isSpaceChar(b))) {
            buf[p++] = (char) b;
            b = readByte();
        }
        return n == p ? buf : Arrays.copyOf(buf, p);
    }

    private char[][] nm(int n, int m) {
        char[][] map = new char[n][];
        for (int i = 0; i < n; i++) map[i] = ns(m);
        return map;
    }

    private int[] na(int n) {
        int[] a = new int[n];
        for (int i = 0; i < n; i++) a[i] = ni();
        return a;
    }

    private int ni() {
        int num = 0, b;
        boolean minus = false;
        while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')) ;
        if (b == '-') {
            minus = true;
            b = readByte();
        }

        while (true) {
            if (b >= '0' && b <= '9') {
                num = num * 10 + (b - '0');
            } else {
                return minus ? -num : num;
            }
            b = readByte();
        }
    }

    private long nl() {
        long num = 0;
        int b;
        boolean minus = false;
        while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')) ;
        if (b == '-') {
            minus = true;
            b = readByte();
        }

        while (true) {
            if (b >= '0' && b <= '9') {
                num = num * 10 + (b - '0');
            } else {
                return minus ? -num : num;
            }
            b = readByte();
        }
    }

    private boolean oj = System.getProperty("ONLINE_JUDGE") != null;

    private void debug(Object... o) {
        if (!oj) System.out.println(Arrays.deepToString(o));
    }

    private void debug(Object a, Object o) {
        if (!oj) {
            System.out.println(a.toString() + ": " + o.toString());
        }
    }
}