發送短信 : Queuing systems (in hospitals)

 ______     _____     ______    ______    ______  
|      \\  |  ___||  /_   _//  /_   _//  /_   _// 
|  --  //  | ||__    `-| |,-    -| ||-     | ||   
|  --  \\  | ||__      | ||     _| ||_    _| ||   
|______//  |_____||    |_||    /_____//  /__//    
`------`   `-----`     `-`'    `-----`   `--`