Implicit Differentiation Problem

Hi,

This is the last one before everyone here thinks Im taking liberities!

Got this expression

cos y - x^2y^3 + 2y = pi

and have to put it in the form of f(x,y)

My understanding is that pi would disappear with it being a constant but I feel this is not right?

can the middle variables of x and y be sorted by using the product rule?

Sorry to put loads of posts up at once but Im playing catch up as being a fire fighter is not the best profession to have whilst learning calculus at home!

Cheers again