class Building{}
public class House extends Building {
  pubilc static void main(String[] args) {
    Building build1=new Building();
    House h1=new House();
    House h2=(House) build; // lineA
    object obj1=(object) build1;
    String str1 =(String) build1; // lineB
    Building build2 = (Building) h1;
  }
  }