content: public class Zoo {
  
      private int x;
      private static float y = Zoo.z;
      public static float z;
  
      protected void m() {
          this.x = 8;
      }
      public static void n() {
          Zoo.y = 8;
      }
  
      private class Boo {}
  
      public static class Animal {
          protected int peso;
          public Animal(int peso) {
              this.peso = peso;
          }
          public void eat(Animal a) {
              this.peso += a.peso;
          }
      }
  
      public static class Dog extends Animal {
  
          public Dog(int peso) {
              super(peso);
          }
  
          @Override
          public void eat(Animal a) {
              this.peso += a.peso / 2;
          }
      }
  
      public static class Labrador extends Dog {
  
          public Labrador(int peso) {
              super(peso);
          }
  
          @Override
          public void eat(Animal a) {
              this.peso += a.peso * 2;
          }
  
          public void drool() {}
  
      }
  
      public static void main(String[] args) {
          Animal a = new Labrador(15);
          a.eat(new Dog(10));
  
      }
  
  
  }
  