private ArrayList<Integer> missingNumbersBlock(int x, int y) {
		ArrayList<Integer> numbers = new ArrayList<Integer>();
		for (int row = 0; row < 3; row++) {
			for (int col = 0; col < 3; col++) {
				numbers.add(sudoku.get(x * 3 + row, y * 3 + col));
			}
		}
		numbers = Util.findMissing(numbers);
		return numbers;
	}