mod_rewrite clashing


I currently have a mod_rewrite for a profile system where users can go onto other users profiles e.g

However this would cause problems if a user attempted to go on a profile that had an actual directory on my server e.g

My question is how can I add an exemption to these directories so they do not work with the mod_rewrite.

#insert before your RewriteRule
RewriteCond %{REQUEST_URI} !(images|files)