I'm trying to make site.com/category/sub-category
redirect to www.site.com/category/sub-category

This is what I have so far:
RewriteCond %{HTTP_HOST} ^site\.com$ [NC]
RewriteRule ^(.*)$ http://www.site.com/$1 [R=301,L]

It works for the second level (site.com/category) but not the third (site.com/category/sub-category).

How would you modify this to work for the third level?

Thank You E