//PROGRAM 7-8
class A {
  private int a;
	
  public void setA(int nilai) {
    a = nilai;
  }
	
  public int getA() {
    return a;
  }
}

class B extends A {
  private int b;
	
  public void setB(int nilai) {
    b = nilai;
  }
	
  public int getB() {
    return b;
  }
}

class C extends B {
  private int c;
	
  public void setC(int nilai) {
    c = nilai;
  }
	
  public int getC() {
    return c;
  }
}

class D extends C {
  private int d;
	
  public void setD(int nilai) {
    d = nilai;
  }
	
  public int getD() {
    return d;
  }
}

class DemoTurunanBertingkat {	
  public static void main(String[] args) {			
    
    // membentuk objek dari kelas D
    D obj = new D();
    
    // mengisi nilai
    obj.setA(10);
    obj.setB(20);
    obj.setC(30);
    obj.setD(40);
    
    // menampilkan nilai
    System.out.println("Nilai a : " + obj.getA());
    System.out.println("Nilai b : " + obj.getB());
    System.out.println("Nilai c : " + obj.getC());
    System.out.println("Nilai d : " + obj.getD());    
  }		
}