private int getNextPossibleNumber(int[][] game, int x, int y, List<Integer> numbers) {
        while (numbers.size() > 0) {
            int number = numbers.remove(0);
            if (isPossibleX(game, y, number) && isPossibleY(game, x, number) && isPossibleBlock(game, x, y, number))
                return number;
        }
        return -1;
    }