Single page count posts id

I’m creating a single page. I want each section to have an id, starting with 1. Here’s what I have now:

<?php
$args = array(
    'sort_order' => 'ASC',
    'sort_column' => 'menu_order', //post_title
    'hierarchical' => 1,
    'exclude' => '',
    'child_of' => 0,
    'parent' => -1,
    'exclude_tree' => '',
    'number' => '',
    'offset' => 0,
    'post_type' => 'page',
    'post_status' => 'publish'
);
$pages = get_pages($args);
//start loop
foreach ($pages as $page_data) {
    $content = apply_filters('the_content', $page_data->post_content);
    $title = $page_data->post_title;
    $slug = $page_data->post_name;
?>
<div id="<?php echo $i++; ?>" class='<?php echo "$slug" ?>'><a name='<?php echo "$slug" ?>'></a>
        <h1><?php echo "$title" ?></h1>
            <?php echo "$content" ?>
</div>

<?php } ?>

The only problem is, that it starts to count with the second section, not the first. The ID of the first section is empty. Here’s the output:

<div id=""></div>
<div id="1"></div>
<div id="2"></div>
...

What have I done wrong?