發送短信 : On Perfect Cayley Graphs

  ______   _    _     ____      _____    _____    
 /_____// | || | ||  |  _ \\   |  ___|| |  __ \\  
 `____ `  | || | ||  | |_| ||  | ||__   | |  \ || 
 /___//   | \\_/ ||  | .  //   | ||__   | |__/ || 
 `__ `     \____//   |_|\_\\   |_____|| |_____//  
 /_//       `---`    `-` --`   `-----`   -----`   
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