24675번 - Two Permutations 다국어

문제

Find the number of pairs $(p, q)$ of permutations of length $n$ such that $\sum\limits_{i=1}^n \max(p_i, q_i) = k$.

As the answer may be large, find it modulo 10ドル^9 + 7$.

입력

The only line contains two integers, $n$ and $k$ (1ドル \le n \le 100,ドル 1ドル \le k \le n^2$).

출력

Print the answer modulo 10ドル^9 + 7$.

제한

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