Melissa recently paid $860 for round-trip airfare to San Francisco to attend a business conference for three days. Melissa also paid the following expenses: $565 fee to register for the conference, $345 per night for three nights' lodging, $230 for meals in restaurants, and $155 for cab fare. (Do not round intermediate calculations. Round your final answers to the nearest whole dollar amount. Leave no answers blank. Enter zero if applicable.)

c. Suppose that Melissa made the trip to San Francisco primarily to visit the national parks and only attended the business conference as an incidental benefit of being present on the coast at that time. What amount of the airfare can Melissa deduct as a business expense?