package action;

class Tmp
{
boolean b;

public boolean isB() {
  return b;
}

public void setB(boolean b) {
  this.b = b;
}

}

class Alpha implements Runnable
{
Tmp o;

public Alpha(Tmp o)
{
  this.o=o;
  
}

@Override
public void run() {
  
  
  for(int i='A';i<='Z';i++)
  {
    
    try {
      synchronized(o)
      {
        
        while(o.b==false)
        {
          try {
            o.wait();
          } catch (InterruptedException e) {
            
            e.printStackTrace();
          }
        } 
      System.out.println((char)i);
      
      o.b=false;
      
      o.notify();
      
        
      }
      
      
      
    } catch (Exception e) {
      
      e.printStackTrace();
    }
  }
  
  
}

}

class Num implements Runnable
{
Tmp o;

public Num(Tmp o)
{
  this.o=o;

}

@Override
public void run() {
  
  for(int i=1;i<=26;i++)
  {
    
    
    try {
      
      synchronized(o)
      {
        while(o.b==true)
        {
          try {
            o.wait();
          } catch (InterruptedException e) {
            
            e.printStackTrace();
          }
        } 
      
      System.out.println(i);
      o.b=true;
      o.notify();
        
      }
    } catch (Exception e) {
      
      e.printStackTrace();
    }
  }
  
  
}

}

public class Test01 {
static Tmp o=new Tmp();

public static void main(String[] args) throws InterruptedException {
  Thread t1=new Thread(new Alpha(o),"t1");
  Thread t2=new Thread(new Num(o),"t2");
  t1.start();
  t2.start();
  t1.join();
  t2.join();
  System.out.println("All over.");
  

}

}