How to get the direct category of the post ?

Hi everybody,

I am creating a my wordpress theme. But i need some help to display category.In my theme i have categories, sub categories, pages and posts organized like this:

Cat1
               ---post101
Cat2
    --Sub cat21
               ---post211
               ---post212
    --Sub cat22
               ---post221
               ---post222
Cat3
    --Sub cat31
Cat4

I use following code in my index.php to retrieve categories of the current post :

<div class="categorieformat">
	| 	Cat&eacute;gorie:<br/> <?php the_category(', ') ?>
	</div>

This code applied in post211 gives me sub cat21 and cat2.
I want just to have the subcategory of post211 and category of the post101. Just the category one level up.

Thanks