I need some help with this question please: I believe the punnett square should be PPxpp = Pp Pp Pp, pp is this right? and what is the pattern?

I need some help with this question please: I believe the punnett square should be PPxpp = Pp Pp Pp, pp is this right? and what is the pattern? Thanks

A species of corn has three colours. Corn may be yellow, white or cream coloured. The cream colour is a mix of the yellow and white colours.