How to ignore specific subdomain with regex

Traefik Traefik v1
,
1

I am using traefik v1.7 and I have a domain name example.com now what I want is to ignore this specific subdomain admin , sync , manage , schedule . in regex expr wild card pattern domain like this :-
"traefik.frontend.rule=HostRegexp: example.com, {subdomain:[a-z]+}.example.com"

So how to do this.