How to trim QUERY_STRING from mod_rewrite redirect

Quick issue = quick solution.

How to trim out a QUERY_STRING from mod_rewrite redirect?

RewriteEngine On
RewriteCond %{QUERY_STRING} z=([0-9]*)&x=([0-9]*)&y=([0-9]*)&r=mapnik
RewriteRule tiles.php http://a.tile.openstreetmap.org/%1/%2/%3.png [NC,L,R=301]

After accessing file:
tiles.php?z=6&x=35&y=21&r=mapink

you will be redirected to
http://a.tile.openstreetmap.org/6/35/21.png?z=6&x=35&y=21&r=mapink

The query string params are appended by default. To trim out the parameters, just place an ending ? (question mark) to redirect rule. That means, that there should be no parameters. Finally:

RewriteEngine On
RewriteCond %{QUERY_STRING} z=([0-9]*)&x=([0-9]*)&y=([0-9]*)&r=mapnik
RewriteRule tiles.php http://a.tile.openstreetmap.org/%1/%2/%3.png? [NC,L,R=301]