Investors & landlords

I am in the same situation for the most part but my lot I sold was included with the purchase of my house.  I sold my house in 2018 and kept the lot (two separate parcels numbers).  When I put in my purchase value, do I put in what I paid for the house with lot (since they were purchased together and came together) in 1991?

 

Please advise.  Any help is greatly appreciated.

Thank you.

Val