Mashed Potato Inc. purchased a machine in January of 2009 for $20,000. The machine had an estimated useful life of 10 years, no salvage value, and was depreciated on a straightline basis. At the beginning of 2018, Mashed Potato overhauled the machine at a cost of $50,000, which the extended the machines original life by 5 years. What is the amount of depreciation expense for the machine in 2018?