atcoder#AGC005D. [AGC005D] ~K Perm Counting

[AGC005D] ~K Perm Counting

Score : 900900 points

Problem Statement

Snuke loves permutations. He is making a permutation of length NN.

Since he hates the integer KK, his permutation will satisfy the following:

  • Let the permutation be a1,a2,...,aNa_1, a_2, ..., a_N. For each i=1,2,...,Ni = 1,2,...,N, aiiK|a_i - i| \neq K.

Among the N!N! permutations of length NN, how many satisfies this condition?

Since the answer may be extremely large, find the answer modulo 924844033924844033(prime).

Constraints

  • 2N20002 \leq N \leq 2000
  • 1KN11 \leq K \leq N-1

Input

The input is given from Standard Input in the following format:

NN KK

Output

Print the answer modulo 924844033924844033.

3 1
2

22 permutations (1,2,3)(1, 2, 3), (3,2,1)(3, 2, 1) satisfy the condition.

4 1
5

55 permutations (1,2,3,4)(1, 2, 3, 4), (1,4,3,2)(1, 4, 3, 2), (3,2,1,4)(3, 2, 1, 4), (3,4,1,2)(3, 4, 1, 2), (4,2,3,1)(4, 2, 3, 1) satisfy the condition.

4 2
9
4 3
14
425 48
756765083