Mr$.$ Quixote is considering an investment in alternative energy. He estimates that the project has annual cash inflows of $$4,200,$$$5,100,$$$6,300,$ and $$5,500,$ for the next four years, respectively. The discount rate is $15$ percent.

What is the discounted payback period for these cash flows if the initial cost is $$9,000?($Do not round intermediate calculations and round your answer to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

Discounted payback period

years