private int compare(String a,String b){
		//a.
		Pattern p = Pattern.compile("(\\w{3,4})(\\d{3})");
		Matcher ma = p.matcher(a);
		Matcher mb = p.matcher(b);
		boolean boo = ma.matches() && mb.matches();
		assert boo;
		
		int ia = Integer.parseInt(ma.group(2));
		int ib = Integer.parseInt(mb.group(2));
		if(ia == ib){
			return a.compareTo(b);
		}else {
			return ia - ib;
		}
	}