@Override
	public void update(GameContainer container, StateBasedGame game, int delta)
			throws SlickException {
		Input input = container.getInput();
		int mouseX = Mouse.getX();
		int mouseY = HEIGHT - Mouse.getY();
		
		if((mouseX > exitButtonX1 && mouseX < exitButtonX2) 
				&& (mouseY > exitButtonY1 && mouseY < exitButtonY2)) {
			if (input.isMouseButtonDown(0)) { 
				System.exit(0); 
			}
		}
	}