How to structure sub catergorys

[jg100]

due to out database each sub category has to be assigned to a category. i.e. /abc would have to be assigned to the category ''letters'  in the url structure; so...it would be www.example.com/letters/abc .

The question is does is matter which way round the category and sub are arranged? Assuming we are optimizing for ''abc' , does it matter if we structured as;

www.example.com/letters/abc

www.example.com/abc/letters

Thanks in advance.

[ClickConsult]

It's best to have the keywords that you're targeting as close to domain as possible although it wouldn't matter when you have just two short folder names such as /letters/abc.

Good luck!