During the current year, Roberta purchases a beachfront condominium for $600,000, paying $150,000 down and taking out a $450,000 mortgage, secured by the property. At the time of the purchase, the outstanding mortgage remaining from the purchase of her principal residence is $700,000. This debt is secured by the residence and the fair market value of the principal residence is $1,400,000. Roberta purchased the principal residence in 1996. What is the amount of qualified indebtedness on which Roberta may deduct the interest payments?