Cotton, an intelligent albino guinea pig consumes only two goods: greens and hay. Her preferences are represented by the utility function U(x,y)=x-x2/2+y, where x is her consumption of greens, and y is her consumption of hay. Cotton always maximizes her utility subject to her budget constraint. Cotton has an income of $m and she is allowed to spend as she wishes on greens and hay. The price of hay is always $1 and the price of greens is Px.

What is Cotton's inverse demand function for greens?