You plan on going on a 9 month vacation 9 months from now. You can pay $3,303 per month during the vacation, or you can pay $20,078 today. If you pay today, how much does it save (or cost) you in present value term if your investments earn 3.13% APR (compounded monthly)? If it costs you more to pay today, state your answer with a negative sign (eg., -2000)