What would be caesar's usenet number?

ROT13 ("rotate by 13 places", usually hyphenated ROT-13) is a simple Caesar cipher used for obscuring text by replacing each letter with the letter thirteen places down the alphabet. A becomes N, B becomes O, and so on up to M, which becomes Z, then the sequence reverses: N becomes A, O becomes B, and so on to Z, which becomes M. The algorithm is used in online forums as a means of hiding joke punchlines, puzzle solutions, movie and story spoilers, and offensive materials from the casual glance. ROT13 has been described as the "Usenet equivalent of a magazine printing the answer to a quiz upside down" .