named routes problem

Hello everybody,

               I have one doubt,In routes i have mentioned as following,

       map.blogpost ':controller/:action/:id',
            :controller => 'a',
            :action => 'blogpost'

       map.help_pages ':controller/:action/:fn',
            :controller => 'a',
            :action => 'help_pages'

is that correct or wrong? because if i put like this then the blog is
working perfectly.if i put the help_pages on the top then the help pages
working perfectly.because the format of routes is same but the name and
parameters name is being to resolve this.Please anyone
know the solution for this please let me know.

Thanks & Regards,