Sarantuya, a college student, feels that now is a good time to buy stocks. However, because she doesn't have any savings, she decides to borrow $22,000 at an annual interest rate of 9 percent. She must make an interest-only payment each year for five years plus repay the entire principal in year five. On August 1, 20X8 when Sarantuya obtained the loan, Sarantuya invested $13,500 in several individual stocks and used the remaining $8,500 to pay her tuition for the year. Assuming Sarantuya's net investment income this year is greater than her investment interest expense this year, how much investment interest expense can she deduct in 20X8?