arcgis desktop - Using Field Calculator to assign values to only Odd (or Even) page fields for Data Driven Pages?

I am creating a map book but do not want the page numbers for each map page to be on the same side (since its printed double sided), I need the page numbers to be placed on opposite sides.

I am using data driven pages. On a previous post it was mentioned to use ODD and EVEN pages per How to make Map Book with facing pages numbered near outside edge?.

However I have over 200 pages.

Is there a "creative" field calculator expression to use?