Deborah got it right. However, I wanted to interject that the VPI designation is very important, in that it let's you know which line the Axanthic is attached to. This is important, because Axanthism is one of the few genes that have numerous lines, which are not compatible with each other. Meaning if you breed a VPI Het Axanthic to a TSK (The Snake Keeper) line Het Axanthic together, you will not haych Axanthics.

Make sure you keep your Axanthic lines the same, and if you choose to work with more than one line, make sure you get good records and photos of all of your animals, to avoid issues in the future.