A contest is approaching, and Kirill has prepared a superdifficult set of tests and answers to them. Unfortunately, he forgot to backup the tests, and, after an update of the Hardsoft Doors operating system, all the test were lost. It will take some time before Kirill invents the Awesome Backup System, but that’s a different story.
，接受失败，是我们不常听到或看到的一个命题，
