.htaccess - Removing 2 directory and php from url -

my current url is:

http://example.org/dir1/dir2/profile.php?username=someone

i want this:

http://example.com/someone

my .htaccess file in public_html folder , empty.

please, can me?

try :

rewriteengine on rewritebase / rewritecond %{request_filename} !-d rewritecond %{request_filename} !-f rewriterule ^([a-za-z0-9_-]+)/?$ /dir1/dir2/profile.php?username=$1 [qsa,l,nc] 

the conditions make sure don't rewrite existing file/directories on server.