class A{                         //常
	int x,y;
	public A(int x,int y){           //๹췽
	   this.x=x;  this.y=y;
	}
	public void display(){ System.out.println("In class A: x="+x+" , y="+y);}
}
class B extends A{                 //
	int a,b;
	public B(int x,int y,int a,int b){   //๹췽
	   super(x,y);this.a=a; this.b=b;
	}
	public void display(){           //д
	   super.display();
	   System.out.println("In class B: a="+a+" , b="+b);
	}
}
public class SuperDemo{
	public static void main(String[]args){
	   B a=new B(1,2,3,4);
	   a.display();
	}
}