description: Alice and Borys are playing tennis.
  
  A tennis match consists of games. In each game, one of the players is serving and the other one is receiving.
  
  Players serve in turns: after a game where Alice is serving follows a game where Borys is serving, and vice versa.
  
  Each game ends with a victory of one of the players. If a game is won by the serving player, it's said that this player holds serve. If a game is won by the receiving player, it's said that this player breaks serve.
  
  It is known that Alice won a games and Borys won b games during the match. It is unknown who served first and who won which games.
  
  Find all values of k such that exactly k breaks could happen during the match between Alice and Borys in total.
  
  Input
  
  Each test contains multiple test cases. The first line contains the number of test cases t (1 ≤ t ≤ 10^3). Description of the test cases follows.
  
  Each of the next t lines describes one test case and contains two integers a and b (0 ≤ a, b ≤ 10^5; a + b > 0) — the number of games won by Alice and Borys, respectively.
  
  It is guaranteed that the sum of a + b over all test cases does not exceed 2 ⋅ 10^5.
  
  Output
  
  For each test case print two lines.
  
  In the first line, print a single integer m (1 ≤ m ≤ a + b + 1) — the number of values of k such that exactly k breaks could happen during the match.
  
  In the second line, print m distinct integers k_1, k_2, …, k_m (0 ≤ k_1 < k_2 < … < k_m ≤ a + b) — the sought values of k in increasing order.
  
  Example
  
  Input
  
  
  3
  2 1
  1 1
  0 5
  
  
  Output
  
  
  4
  0 1 2 3
  2
  0 2
  2
  2 3
  
  Note
  
  In the first test case, any number of breaks between 0 and 3 could happen during the match: 
  
    * Alice holds serve, Borys holds serve, Alice holds serve: 0 breaks; 
    * Borys holds serve, Alice holds serve, Alice breaks serve: 1 break; 
    * Borys breaks serve, Alice breaks serve, Alice holds serve: 2 breaks; 
    * Alice breaks serve, Borys breaks serve, Alice breaks serve: 3 breaks. 
  
  
  
  In the second test case, the players could either both hold serves (0 breaks) or both break serves (2 breaks).
  
  In the third test case, either 2 or 3 breaks could happen: 
  
    * Borys holds serve, Borys breaks serve, Borys holds serve, Borys breaks serve, Borys holds serve: 2 breaks; 
    * Borys breaks serve, Borys holds serve, Borys breaks serve, Borys holds serve, Borys breaks serve: 3 breaks. 
solution: import java.io.*;
  import java.util.*;
  
  public class CF_1561b{
      public static final void main(String[] args){
          Kattio io= new Kattio();
          int t= io.getInt();
          while(t-->0){
              int a= io.getInt(), b= io.getInt(), extra= 0;
              int games= a+b;
              if(games%2==1){
                  if(a>b){
                      a-= 1;
                      extra+= 1;
                  }else{
                      b-= 1;
                      extra+= 1;
                  }
              }
              // a+b is now even
              int halfAB= (a+b)/2;
              int minBreaks= Math.abs(a-halfAB), maxBreaks= a+b-minBreaks;
  
              List<String> ks= new ArrayList<>();
              for(int i=minBreaks; i<=maxBreaks; i+=2){
                  ks.add(String.valueOf(i));
                  if(extra!=0) ks.add(String.valueOf(i+1));
              }            
              io.println(ks.size());
              io.println(String.join(" ", ks));
          }
          io.close();
      }
  
      static void err(String format, Object... args){
          System.err.println(String.format(format, args));
      }    
      static class Kattio extends PrintWriter {
          private BufferedReader r;
          private String line, token;
          private StringTokenizer st;
      
          public Kattio(){this(System.in);}
          public Kattio(InputStream i){
          super(new BufferedOutputStream(System.out));
              r= new BufferedReader(new InputStreamReader(i));
          }
          public Kattio(InputStream i, OutputStream o){
          super(new BufferedOutputStream(o));
              r= new BufferedReader(new InputStreamReader(i));
          }
          public boolean isLineEnd(){
              return !st.hasMoreTokens();
          }
          public boolean hasMoreTokens(){
              return peekToken()!=null;
          }
          public int getInt(){
              return Integer.parseInt(nextToken());
          }
          public double getDouble(){ 
              return Double.parseDouble(nextToken());
          }
          public long getLong(){
              return Long.parseLong(nextToken());
          }
          public String getWord(){
              return nextToken();
          }
          private String peekToken(){
              if(token==null) try {
                  while(st==null || !st.hasMoreTokens()) {
                      line= r.readLine();
                      if(line==null) return null;
                      st= new StringTokenizer(line);
                  }
                  token= st.nextToken();
              }catch(IOException e){}
              return token;
          }
          private String nextToken() {
              String ans= peekToken();
              token= null;
              return ans;
          }
      }    
  }