Ms. Tweeter is buying a house with a cost of $350,000. She will make a down payment of $20,000 on the house, and the rest will be paid for with a mortgage loan. Her mortgage loan has an APR of 4.9% compounded semi-annually, with a weekly payment schedule and a time horizon of 20 years. The first payment is due in one week's time. How much principal have you paid off after 5 years?