private void buttonAction(ActionEvent e, ArrayList<String> ImageSet1, ArrayList<String> ImageSet2) {
		// TODO ڵ  ޼ҵ 
		if(e.getSource().equals(leftButton)) {
			System.out.println("left BUtton clicked : image index = " + (clickCount-1) * 2);
			ImageSet2.add(ImageSet1.get((clickCount - 1) * 2));
		}
		else {
			System.out.println("right BUtton clicked : image index = " + ((clickCount-1) * 2 + 1) );				
			ImageSet2.add(ImageSet1.get((clickCount - 1) * 2 + 1));
		}		
	}