K-1 shares redeemed how to calculate gains

I received my Final K-1 where as a limited partner my shares were redeemed by the partnership.

 

Box 19 has my redeem amount which was also reflected in "withdrawals & distributions" in my L section.

 

I understand there some difference between redemption vs sale of shares. For all intents and purposes it seems this was a redemption event. My question here is what should I use for calculating gains when I was prompted to enter after I checked "disposed my interest in the partnership" checkbox?