On September 27, 2017, you are digging through your fridge to find something for lunch when you find a sandwich from exactly three years ago. You gag as you lift the top slice of bread and you see a small device that is labeled “Alien Beacon” with a countdown on it: 45 minutes. You see five locks on the device and realize that to destroy it and to keep the aliens from coming and abducting both you and your fridge, you need to solve all of the locks to disable the beacon.