Easiest thing, go look at the Microsoft exam certification page where they describe all the exams, list all the exam paths and all the certifications.
I think it's 3, but I'm not looking at the site and could be thinking of some other upgrade.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability