IMO 1988 LL CUB5

Let k be a positive integer and Mk the set of all the integers

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IMO 1988 LL CUB5

Origin: CUB

Problem

Let k be a positive integer and Mk the set of all the integers that are between 2k2 + k and 2k2 + 3k, both included. Is it possible to partition Mk into two subsets A and B such that  x\inA x2 =  x\inB x2?