IMO Shortlist 1966 problem 51


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2. travnja 2012.
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Consider n students with numbers 1, 2, \ldots, n standing in the order 1, 2, \ldots, n. Upon a command, any of the students either remains on his place or switches his place with another student. (Actually, if student A switches his place with student B, then B cannot switch his place with any other student C any more until the next command comes.)

Is it possible to arrange the students in the order n,1, 2, \ldots, n-1 after two commands ?
Izvor: Međunarodna matematička olimpijada, shortlist 1966