RewriteRule: Remove Www From All Url

on my server I'm trying to remove 'www' from all subdomain urls.

For example:
[url]-> should be -> [url]
[url]-> [url]...

what rewrite rules to use?

I suppose I've to put this rule in httpd.conf and apply it at Server level.

I'm using this

RewriteEngine on
RewriteCond %{HTTP_HOST} ^www.([^.]+).example.com
RewriteRule (.*) [url]

where %1 is one subdomain.
The problem is I want this to work on ALL Subdomains.

What rewrite rule should I use?