You have decided to start saving up to buy a house.

You plan on withdrawing $25,000 at the end of year 4 for a down payment, $18,000 at the end of year 5 and again $18,000 at the end of year 6 for upgrades, and $20,000 at the end of year 7 to add a pool.

How much do you need to deposit today into an account with an annual interest rate of 1.25%?

Draw a cash flow diagram and provide the correct function notation.