Only to undesirables. Entry exams at mechmath are composed of written and oral stages; these are the questions asked by examiners at oral stage of examination, one on one with potential student.

Only to the undesirables students. Quoting the paper, "The Mathematics Department of Moscow State University, the most prestigious mathematics school in Russia, was at that time actively trying to keep Jewish students (and other 'undesirables') from enrolling in the department. One of the methods they used for doing this was to give the unwanted students a different set of problems on their oral exam."