Nano Specialist is considering an upgrade project. The estimated cash flows from the upgrade project appear below. What is the project's payback period? Note that year 0 and year 1 cash flows are negative. (Answer in years, round to 2 places)

Year 0 cash flow = -81,000

Year 1 cash flow = -44,000

Year 2 cash flow = 24,000

Year 3 cash flow = 28,000

Year 4 cash flow = 22,000

Year 5 cash flow = 29,000

Year 6 cash flow = 32,000

Year 7 cash flow = 25,000