Piano Question, there are three staffs, two treble clefts on this sheet music below?

http://www.forpiano.com/FILES/a_thousand_miles__vanessa_carlton.pdf

So i found for the sheet music of a thousand miles, there are three staffs, including two treble cleft, Which treble cleft do i play on the piano? the top one or the bottom one? And why are there two treble cleft?
8 answers 8