public interface Animal {
    public int sales();
}

public class Pig implements Animal {
    int price = 10;
    int weight = 200;;
    public int sales() {
        return price * weight;
    }
}

public class Chicken implements Animal {
    int price = 5;
    int weight = 5;
    int egg = 20;
    public int sales() {
        return price * weight + egg;
    }
}

public class Farm {
    public static Animal producePig() {
        return new Pig();
    }
    public static Animal produceChicken() {
        return new Chicken();
    }
}

   
Animal animal1 = Farm.producePig();
Animal animal2 = Farm.produceChicken();
System.out.println("Pig : " + animal1.sales());
System.out.println("Chicken : " + animal2.sales());