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We say that a set X of natural numbers is n-k-special if:
Write a program that:
In the first line of the standard input there are two natural numbers n and k separated by a single space, 1 ≤ n ≤ 100, 0 ≤ k ≤ 400.
In the first line of the standard output there should be written one non-negative integer, which equals the number of n-k-special sets for the given n and k.