Birdco sold a building for $600,000 and received a down payment of $120,000 as well as annual principal payments of $120,000 for each of the subsequent four years. Birdco had purchased the building for $500,000 and claimed depreciation totaling $80,000 during its ownership of the building. What amount of gain should Birdco report on its federal income tax return in the year of sale using the installment method?