Britney Spears Circus Cake Decorations What Is The Original Tune At The Start Of Britney Spears Circus Song?

What is the original tune at the start of britney spears circus song? - britney spears circus cake decorations

You know, Brittany Spears "Circus", the song belongs to refine the EVI theres first, but something could be done through their song, someone help me please? :)