Mashed Potato Inc. purchased a machine in January of 2016 for $20,000. The machine had an estimated useful life of 10 years, no salvage value, and was depreciated on a straight-line basis. At the beginning of 2019, Mashed Potato overhauled the machine at a cost of $50,000, which extended the machines original life by 9 years. What is the amount of depreciation expense for the machine in 2021?