The local Laundromat has just entered the computer age. As each customer enters, he or she puts coins into slot at one of two stations and type in the number of washing machines he$/$she will need. The stations are connected to a central computer that automatically assigns available machines and outputs tokens that identify the machines to be used. The customer puts laundry into the machines and inserts each token into the machine indicated on the token. When a machine finishes its cycle, it informs the computer that it is available again