How to list categories alphabetically?

Question

Joomla

Hello, I have this code

<?php foreach ($this->intro_items as &$item){
      $counter_material +=1;
      $its_a_end = 0;
      if($counter_material==1){
        $counter_column +=1;
        echo '<div class="columns column-'.$counter_column.'">';
        if($first_letter==substr($item->title,0,1)){
          echo '<div class="arhiv_content obchi">';
        }
      }
        if($first_letter!=substr($item->title,0,1)){
          $first_letter = substr($item->title,0,1);
//					echo '-||'.$counter_material.'||-';
          if($counter_material>1) echo '</div>';
          echo '<h3 class="arhiv_letter">'.$first_letter.'</h3>';
          echo '<div class="arhiv_content neobchi">';
        }

      ?>
        <a href="<?php echo JRoute::_(ContentHelperRoute::getArticleRoute($item->slug, $item->catid)); ?>">
          <span>
            <?php echo $item->title; ?>
          </span>
        </a>
      <?php 			
        //echo $counter_material.' >= '.$num_materail_in_column.' || '.$counter_material.' >= '.$num_links."\n";
        //echo $counter_material.'>='.count($this->intro_items)."\n";
        if($counter_material >= $num_materail_in_column||$counter_material>=count($this->intro_items)){
          $counter_material = 0;
          $its_a_end = 1;
            echo '</div>';
          echo '</div>';
        }
      };
      
      if(!$its_a_end){
          echo '</div>';
        echo '</div>';
      }

      ?>

And this is how it is displayed.

That is, for some reason, category A and category N are not displayed correctly. And instead of displaying all categories from A, it displays, as you can see, for some reason one category from A, then two from N.