Computer Science is so hard these days that students in a senior design group have decided to work on a project to have drones fly them dinner while they are hard at work on their coursework. Naturally, the senior design group would like to offer this feature for multiple groups of people, each of who may be located in different places and might want food from different places. The group did a great job with their drone design. It flawlessly picked up food and could fly that food to the appropriate location. Unfortunately, they only built one remote control for the (upto) four drones to deliver food. That means that even if best path for two drones is different, the drones are limited to moving in the same direction each time. Of course, if this were always true, then the drones would rarely be able to complete all of their deliveries. Luckily, however, some areas of the sky are marked as "no-fly zones." Thus, if a drone is directed to move into one of these no-fly zones, instead of moving, it will stay put. This means that with just one controller, different drones might end up moving different paths. Also