private static Point compareSets(ArrayList<Integer> lastSet,
			ArrayList<Integer> valids) {
		int sell = 0;
		int buy = 0;

		for (Integer I : lastSet) {
			if (!valids.contains(I))
				sell++;
		}
		for (Integer I : valids) {
			if (!lastSet.contains(I))
				buy++;
		}

		return new Point(buy, sell);
	}