solve by showing equations and work, No Table please!

A project promises cash inflows of $2,000 the end of Year 1 and $5,000 at the end of Year 4. The project requires an initial investment of $4,000 and another investment of $1,000 at the end of Year 3. If the company's cost of capital is 6% and buffer margin is 2%, what is the NPV of the project