New Line Character in Validation Rules?

I'm trying to work out a way to test the location of a New Line in a Validation Rule as I want to check to make sure whether the first line of the billing address is less than 30 characters long. I believe I could use FIND(search_text, text [, start_num]) , but I'm not sure what text I should use for the new line. Anyone have any ideas?

Thanks,
Michael