What is the payback period of this project?

What is the discounted payback period of this project?

IGT, Inc. is considering a project that costs $45 million and provides cash flows of $20 million for the first year, $30 million for year two, and $20 million for year three. Assume a weighted average cost of capital of 11%. Year 0 Year 1 Year 2 |-45M 20M 30M Here M is million $ Year 3 20M