Problem: 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.

Solution (in JAVA):

Solution:
//Some of the methods are copied from GeeksforGeeks Website  
import java.util.*;
import java.lang.*;
import java.io.*;
public class Main
{ 
  static  Reader sc=new Reader();
  // static FastReader sc=new FastReader(System.in);
  static long isSet(long n,long k)
   {
      long one=1,zero=0;
       if ((n & (one << (k-one))) > zero) return one;
       return zero;
   }
static boolean valid(ArrayList<Long> al,long and,long xor,long sum)
{
   long and2=0,xor2=0,sum2=0;
   for(int i=0;i<al.size();i++)
     {
        long e=al.get(i);
        and2&=e;
        xor2^=e;
        sum2+=e;
     }
   //out.println(and+" "+and2+" "+xor+" "+xor2+" "+sum+" "+sum2);
   return  xor==xor2 && sum==sum2 ;
}
 public static void main (String[] args) throws java.lang.Exception
   {
	try{
	    /*
	        int n=sc.nextInt();
	        ArrayList<Integer> al=new ArrayList<>();
	        ArrayList<Long> al=new ArrayList<>();
	        Set<Integer> set=new HashSet<>();
	        Collections.sort(al,Collections.reverseOrder());
	     
	        long n=sc.nextLong();
	        for(int i=0;i<n;i++) 
	        String s=sc.next();
	        StringBuilder sb=new StringBuilder();
	     */
		  int t = 1;// sc.nextInt();
		  while(t-->0)
		    { 
		      long u=sc.nextLong();
		      long v=sc.nextLong();
		      long xor=u;
		      long sum=v;
		      long and=(v-u)/2;
		      String sb="";
		      boolean flag=true;
		       boolean f=false;
		      ArrayList<Long> al=new ArrayList<>();
		      for(long i=63;i>=1;i--)
		        {
		           long xor_bit=isSet(xor,i);
		           long and_bit=isSet(and,i);
		           long bit=0;
		          
		           if(xor_bit==0)
		             {
		                if(and_bit==0)
		                  {
		                     bit=0;
		                  }
		                else
		                  {
		                     bit=1;
		                  }
		             }
		          else
		             {
		                if(and_bit==0)
		                 {
		                    bit=1;
		                 }
		                else
		                 {
		                    f=true;
		                 }
		             }
		         if(f) break;
		         sb+=bit;
		        }
		      if(!f)
		        {
		           long res=Long.parseLong(sb,2);
		           if(res>0)
		             al.add(res);
		           if(sum-res>0)
		             al.add(sum-res);
		        }
		    else
		       {
		         if(xor>0)
		         al.add(xor);
		         if(and>0)
		         al.add(and);
		         if(and>0)
		         al.add(and);
		       }
		       
		      flag=valid(al,and,xor,sum);
		      //print_long(al);
		      if(flag)
		      {
		         out.println(al.size());
		         print_long(al);
		      }
		      else
		        out.println("-1");
		    }
	     out.flush();
	     out.close();
	   }     
	catch(Exception e)
		 {}
	}
 
 /*
   ...SOLUTION ENDS HERE...........SOLUTION ENDS HERE...
 */
 
static void flag(boolean flag)
   {
       out.println(flag ? "YES" : "NO");
       out.flush();
   }
   
 /*                     
    Map<Long,Long> map=new HashMap<>();
             for(int i=0;i<n;i++)
               {
                  if(!map.containsKey(a[i]))
                   map.put(a[i],1);
                 else
                   map.replace(a[i],map.get(a[i])+1);
               }
     
    Set<Map.Entry<Long,Long>> hmap=map.entrySet();
             for(Map.Entry<Long,Long> data : hmap)
               {
          
               }
       
   Iterator<Integer> it = set.iterator();
          while(it.hasNext()) 
           { 
            int x=it.next();
           }
   */

static void print(int a[])
  {
     int n=a.length;
     for(int i=0;i<n;i++)
       {
          out.print(a[i]+" ");
       }
     out.println();
     out.flush();
  }
static void print(long a[])
  {
     int n=a.length;
     for(int i=0;i<n;i++)
       {
          out.print(a[i]+" ");
       }
     out.println();
     out.flush();
  } 
static void print_int(ArrayList<Integer> al)
  {
     int si=al.size();
     for(int i=0;i<si;i++)
       {
          out.print(al.get(i)+" ");
       }
     out.println();
     out.flush();
  }
static void print_long(ArrayList<Long> al)
  {
     int si=al.size();
     for(int i=0;i<si;i++)
       {
          out.print(al.get(i)+" ");
       }
     out.println();
     out.flush();
  }

static class Graph
  {
        int v;
        ArrayList<Integer> list[];
        Graph(int v)
        {
            this.v=v;
            list=new ArrayList[v+1];
            for(int i=1;i<=v;i++)
                list[i]=new ArrayList<Integer>();
        }
        void addEdge(int a, int b)
        {
            this.list[a].add(b);
        }
    }
static void DFS(Graph g, boolean[] visited, int u)
	{
        visited[u]=true;
        int v=0;
        for(int i=0;i<g.list[u].size();i++)
        {
            v=g.list[u].get(i);
            if(!visited[v])
               DFS(g,visited,v);
        }
  } 
  
// static class Pair
//    {
//       int x,y;
//       Pair(int x,int y)
//        {
//           this.x=x;
//           this.y=y;
//        }
//    }
   
static long sum_array(int a[])
 {
    int n=a.length;
    long sum=0;
    for(int i=0;i<n;i++)
     sum+=a[i];
    return sum;
 }
static long sum_array(long a[])
 {
    int n=a.length;
    long sum=0;
    for(int i=0;i<n;i++)
     sum+=a[i];
    return sum;
 }

 static void sort(int[] a) 
   {
		ArrayList<Integer> l=new ArrayList<>();
		for (int i:a) l.add(i);
		Collections.sort(l);
		for (int i=0; i<a.length; i++) a[i]=l.get(i);
	}
static void sort(long[] a) 
   {
		ArrayList<Long> l=new ArrayList<>();
		for (long i:a) l.add(i);
		Collections.sort(l);
		for (int i=0; i<a.length; i++) a[i]=l.get(i);
	}

static void reverse_array(int a[])
 {
    int n=a.length;
    int i,t; 
    for (i = 0; i < n / 2; i++) { 
            t = a[i]; 
            a[i] = a[n - i - 1]; 
            a[n - i - 1] = t; 
        } 
 }
static void reverse_array(long a[])
 {
    int n=a.length;
    int i; long t; 
    for (i = 0; i < n / 2; i++) { 
            t = a[i]; 
            a[i] = a[n - i - 1]; 
            a[n - i - 1] = t; 
        } 
 }
 
static long gcd(long a, long b) 
    { 
        if (a == 0) 
            return b; 
          
        return gcd(b%a, a); 
    } 
static int gcd(int a, int b) 
    { 
        if (a == 0) 
            return b; 
          
        return gcd(b%a, a); 
    } 

   static class FastReader{
 
        byte[] buf = new byte[2048];
        int index, total;
        InputStream in;
 
        FastReader(InputStream is) {
            in = is;
        }
 
        int scan() throws IOException {
            if (index >= total) {
                index = 0;
                total = in.read(buf);
                if (total <= 0) {
                    return -1;
                }
            }
            return buf[index++];
        }
 
        String next() throws IOException {
            int c;
            for (c = scan(); c <= 32; c = scan());
            StringBuilder sb = new StringBuilder();
            for (; c > 32; c = scan()) {
                sb.append((char) c);
            }
            return sb.toString();
        }
 
        int nextInt() throws IOException {
            int c, val = 0;
            for (c = scan(); c <= 32; c = scan());
            boolean neg = c == '-';
            if (c == '-' || c == '+') {
                c = scan();
            }
            for (; c >= '0' && c <= '9'; c = scan()) {
                val = (val << 3) + (val << 1) + (c & 15);
            }
            return neg ? -val : val;
        }
 
        long nextLong() throws IOException {
            int c;
            long val = 0;
            for (c = scan(); c <= 32; c = scan());
            boolean neg = c == '-';
            if (c == '-' || c == '+') {
                c = scan();
            }
            for (; c >= '0' && c <= '9'; c = scan()) {
                val = (val << 3) + (val << 1) + (c & 15);
            }
            return neg ? -val : val;
        }
    }
   
    static class Reader 
    { 
        final private int BUFFER_SIZE = 1 << 16; 
        private DataInputStream din; 
        private byte[] buffer; 
        private int bufferPointer, bytesRead; 
  
        public Reader() 
        { 
            din = new DataInputStream(System.in); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        } 
  
        public Reader(String file_name) throws IOException 
        { 
            din = new DataInputStream(new FileInputStream(file_name)); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        } 
  
        public String readLine() throws IOException 
        { 
            byte[] buf = new byte[64]; // line length 
            int cnt = 0, c; 
            while ((c = read()) != -1) 
            { 
                if (c == '\n') 
                    break; 
                buf[cnt++] = (byte) c; 
            } 
            return new String(buf, 0, cnt); 
        } 
  
        public int nextInt() throws IOException 
        { 
            int ret = 0; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
            do
            { 
                ret = ret * 10 + c - '0'; 
            }  while ((c = read()) >= '0' && c <= '9'); 
  
            if (neg) 
                return -ret; 
            return ret; 
        } 
  
        public long nextLong() throws IOException 
        { 
            long ret = 0; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
            do { 
                ret = ret * 10 + c - '0'; 
            } 
            while ((c = read()) >= '0' && c <= '9'); 
            if (neg) 
                return -ret; 
            return ret; 
        } 
  
        public double nextDouble() throws IOException 
        { 
            double ret = 0, div = 1; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
  
            do { 
                ret = ret * 10 + c - '0'; 
            } 
            while ((c = read()) >= '0' && c <= '9'); 
  
            if (c == '.') 
            { 
                while ((c = read()) >= '0' && c <= '9') 
                { 
                    ret += (c - '0') / (div *= 10); 
                } 
            } 
  
            if (neg) 
                return -ret; 
            return ret; 
        } 
  
        private void fillBuffer() throws IOException 
        { 
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
            if (bytesRead == -1) 
                buffer[0] = -1; 
        } 
  
        private byte read() throws IOException 
        { 
            if (bufferPointer == bytesRead) 
                fillBuffer(); 
            return buffer[bufferPointer++]; 
        } 
  
        public void close() throws IOException 
        { 
            if (din == null) 
                return; 
            din.close(); 
        } 
    }
  static  PrintWriter out=new PrintWriter(System.out);
  static int int_max=Integer.MAX_VALUE;
  static int int_min=Integer.MIN_VALUE;
  static long long_max=Long.MAX_VALUE;
  static long long_min=Long.MIN_VALUE;
}
// Thank You !