How many instruments do 당신 play?

Just one (at least for now just one). I play the 피아노 but I want to be able to play any other instrument and still be a pianist.

Right now just Cello, but I want to learn 피아노 too.

I play 3 instruments.
My primary instrument is the viola, but I also know how to play the 피아노 and the violin.
I also sing, but the voice usually isn't considered an instrument. If it was, 노래 would be my primary instrument.