public class LightBulb {
	private boolean On;
	
	LightBulb (boolean On)  {
		this.On = On;
	}

	boolean isOn ()	{
		return On;
	}
	
	boolean isOff () {
		return !On;
	}
	
	void turnOn (){
		On = true;
	}
	
	void turnOff (){
		On = false;
	}

	void flip (){
	    On = !On;
	}
}