John and Mary Johnson were divorced in January 2018. By terms of their divorce decree John had to pay alimony to Mary at the rate of $50,000 in 2018, $25,000 in 2019, and zero in 2020. For the first three years of the agreement, determine what portions of the payments are deductible by John and includible in Mary's gross income.

(calculate through alimony recapture) Explanation really appreciated!