An art museum has a pentagon-shaped room. When drawn to scale on a coordinate grid, the corners of the room are points A(14,18) ; B(10,18) ; C(10,9) ; D(12,7) ; E(18,12.5), shown in feet. The walls are 10 feet high. The museum is going to paint four of the walls ab bc de ae . Assume one gallon of paint is enough to cover 268 square feet. How many gallons of paint should the museum purchase? Enter your answer as a whole number.