Partition It

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Chef has the $N$ numbers $1, 2, 3, \dots, N$. He wants to give exactly $K$ of these numbers to his friend and keep the rest with him. He can choose any $K$ numbers such that the [GCD](https://en.wikipedia.org/wiki/Greatest_common_divisor) of any number from Chef's set and any number from his friend's set is equal to $1$. Formally, suppose Chef gives the set of numbers $A$ to his friend and keeps

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solution.cppC++17

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