XYZ Corp., an accrual method taxpayer, owns a rental building. Mr. King, an individual, entered into a two-year lease to rent the building from XYZ Corp. at a rate of $1,000/month. The lease starts on December 1, 2019, and runs through Nov. 30, 2021. On December 1, 2019, Mr. King prepaid his rent for the entire lease ($24,000). For book purposes, XYZ Corp. will not recognize the rental revenue until it is earned ($1,000 in 2019, $12,000 in 2020 and $11,000 in 2021). For tax purposes, how much of the $24,000 must XYZ Corp. include in gross income for 2019?