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

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發送短信 : Elementary Number Theory: Primes, Congruences, and Secrets