abstract class Subjects
{
   int mark;
   String greeting;

   public abstract String Welcome();
   public abstract int Mark();
   public void info()
    {
       mark = Mark();
   	   greeting= Welcome();
       System.out.println("I'm in a class and I say:");
       System.out.println(greeting);
       System.out.println("I've got a very good mark: "+mark+"\n");
    }	
}	
	
class Computer_Science extends Subjects
{
   public String Welcome()
   {
   	   String greeting= "Hello computer science teacher!";
   	   return greeting;
   }
   
   public int Mark()
   {
   	   mark = (int)(Math.random() * 10);
   	   mark++;
   	   return mark;
   }
   
}

class Lithuanian extends Subjects
{
	
	public String Welcome()
	{
	  String greeting= "Hello Lithuanian teacher!";
   	  return greeting; 
	}
	
		
	public int Mark()
	{
	   mark = (int)(Math.random() * 9);
   	   mark++;
   	   return mark;	
	}
	
}