You are a landscaper working on the design of a parking lot in a new shopping center. You are measuring the length of a grass median that will be exactly as long as four parking spots and their dividing lines. One of these spots is a handicapped spot, which is 1018 feet wide and next to the curb. The other three spots are 838 feet wide. There are four dividing lines between the spots, and each measures 18 foot. What is the length of the grass median, D?