interface Device {
    boolean isEnabled();
    void enable();
    void disable();
    int getVolume();
    void setVolume(int percent);
}

class TV implements Device {
    private boolean on = false;
    private int volume = 30;

    public boolean isEnabled() { return on; }
    public void enable() { on = true; }
    public void disable() { on = false; }
    public int getVolume() { return volume; }
    public void setVolume(int percent) { volume = percent; }
}

class Radio implements Device {
    private boolean on = false;
    private int volume = 20;

    public boolean isEnabled() { return on; }
    public void enable() { on = true; }
    public void disable() { on = false; }
    public int getVolume() { return volume; }
    public void setVolume(int percent) { volume = percent; }
}

class Remote {
    protected Device device;
    Remote(Device device) { this.device = device; }

    void togglePower() {
        if (device.isEnabled()) device.disable();
        else device.enable();
    }

    void volumeDown() {
        device.setVolume(device.getVolume() - 10);
    }

    void volumeUp() {
        device.setVolume(device.getVolume() + 10);
    }
}

public static void main(String[] args) {
    TV tv = new TV();
    Remote remote = new Remote(tv);
    remote.togglePower();
    remote.volumeUp();
}