Q:

htaccess add www if not subdomain, if subdomain remove www

I'm trying to make this - probably example would be the best, so:
domain.com -> www.domain.com
www.domain.com -> www.domain.com
subdomain.domain.com -> subdomain.domain.com
www.subdomain.domain.com -> subdomain.domain.com

So if visitor is in subdomain, don't add www and when is set, remove It. Else if not in subdomain, add www.
I tried to write something like this, but this doesn't remove www from subdomain adress :/ Also, if possible, I don't want to use domain and TLD domains but make it as much universal as possible. 
Could you help me where might be the problem please? 
# add www if not subdomain
RewriteCond %{HTTP_HOST} ^[^.]+\.[^.]+$
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [L,R=301]

# remove www if subdomain
RewriteCond %{HTTP_HOST} ^www\.([^\.]*)\.%{HTTP_HOST}+$ [NC]
RewriteRule (.*) http://%1.%{HTTP_HOST}/$1 [R=301,L]

This file I have in root:
# htaccess rules for subdomains and aliases
# to create new subdomain, create a folder www/subdom/(subdomain name)
# to create web for alias, create a folder www/domains/(whole domain name)

# htaccess pravidla pro subdomeny a samostatne weby aliasu
# pro vytvoreni subdomeny vytvorte adresar www/subdom/(nazev subdomeny)
# pro vytvoreni webu pro alias vytvorte adresar www/domains/(cely domenovy nazev)
# dalsi info a priklady: http://kb.wedos.com/r/32/webhosting-htaccess.html

RewriteEngine On

# cele domeny (aliasy)
RewriteCond %{REQUEST_URI} !^domains/
RewriteCond %{REQUEST_URI} !^/domains/
RewriteCond %{HTTP_HOST} ^(www\.)?(.*)$
RewriteCond %{DOCUMENT_ROOT}/domains/%2 -d
RewriteRule (.*) domains/%2/$1 [DPI]

# subdomeny (s nebo bez www na zacatku)
RewriteCond %{REQUEST_URI} !^subdom/
RewriteCond %{REQUEST_URI} !^/subdom/
RewriteCond %{HTTP_HOST} ^(www\.)?(.*)\.([^\.]*)\.([^\.]*)$
RewriteCond %{DOCUMENT_ROOT}/subdom/%2 -d
RewriteRule (.*) subdom/%2/$1 [DPI]

# aliasy - spravne presmerovani pri chybejicim /
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^domains/[^/]+/(.+[^/])$ /$1/ [R]

# subdomeny - spravne presmerovani pri chybejicim /
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^subdom/[^/]+/(.+[^/])$ /$1/ [R]

A:

Have it like this:
# add www if not subdomain
RewriteCond %{HTTP_HOST} ^[^.]+\.[^.]+$
RewriteRule ^ http://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

# remove www if subdomain
RewriteCond %{HTTP_HOST} ^www\.([^.]+\.[^.]+\.[^.]+)$ [NC]
RewriteRule ^ http://%1%{REQUEST_URI} [R=301,L]

