How to change location of snippet?

I have this snippet below and it appears at the beginning of the content (it shows the last updated date of the article), but I want it to appear at the end. How do I do that?

function wpb_last_updated_date( $content ) {
$u_time = get_the_time(‘U’);
$u_modified_time = get_the_modified_time(‘U’);
if ($u_modified_time >= $u_time + 86400) {
$updated_date = get_the_modified_time(‘F jS, Y’);
$updated_time = get_the_modified_time(‘h:i a’);
$custom_content .= ‘<p class=”last-updated”>Last updated on ‘. $updated_date . ‘</p>’;
}

$custom_content .= $content;
return $custom_content;
}
add_filter( ‘the_content’, ‘wpb_last_updated_date’ );