<?php
if ($post->post_parent) {
$ancestors=get_post_ancestors($post->ID);
$root=count($ancestors)-1;
$parent = $ancestors[$root];
} else {
$parent = $post->ID;
} ?>
<?php
if ($post->post_parent) {
$ancestors=get_post_ancestors($post->ID);
$root=count($ancestors)-1;
$parent = $ancestors[$root];
} else {
$parent = $post->ID;
} ?>