abstract class Animal {
}

class Dillo extends Animal {
  double weight;
  boolean alive;
  Dillo(double weight, boolean alive) {
    this.weight = weight;
    this.alive = alive;
  }
}

class Posn {
  int x;
  int y;
  Posn(int x, int y) {
    this.x = x;
    this.y = y;
  }
}

class Ant extends Animal {
  double weight;
  Posn loc;
  Ant(double weight, Posn loc) {
    this.weight = weight;
    this.loc = loc;
  }
}


class Cage {
  Animal a1;
  Animal a2;
  Cage(Animal a1, Animal a2) {
    this.a1 = a1;
    this.a2 = a2;
  }
}


abstract class Grade {
}

class NoGrade extends Grade {
  NoGrade() {
  }
}

class NumGrade extends Grade {
   int n;
   NumGrade(int n) {
     this.n = n;
   }
}