Qianlong's reign saw the launch of several ambitious cultural projects, including the compilation of the Siku Quanshu, or Complete Repository of the Four Branches of Literature. With a total of over 3,400 books, 79,000 chapters, and 36,304 volumes, the Siku Quanshu is the largest collection of books in Chinese history. Nevertheless, Qianlong used Literary Inquisition to silence opposition. The accusation of individuals began with the emperor's own interpretation of the true meaning of the corresponding words. If the emperor decided these were derogatory or cynical towards the dynasty, persecution would begin. Literary inquisition began with isolated cases at the time of Shunzhi and Kangxi, but became a pattern under Qianlong's rule, during which there were 53 cases of literary persecution.

Answer this question, if possible (if impossible, reply "unanswerable"): How many literary persecutions were there under Qianlongs reign?
53