// 抽象类 Animal
abstract class Animal {
    public abstract void makeSound();
}

// 接口 Swimmable
interface Swimmable {
    void swim();
}

// Dog 类继承 Animal 并实现 Swimmable
class Dog extends Animal implements Swimmable {
    @Override
    public void makeSound() {
        System.out.println("狗叫：汪汪汪！");
    }

    @Override
    public void swim() {
        System.out.println("狗会游泳，正在狗刨...");
    }
}

// Cat 类继承 Animal，不实现 Swimmable
class Cat extends Animal {
    @Override
    public void makeSound() {
        System.out.println("猫叫：喵喵喵~");
    }
}