atcoder#ABC253E. [ABC253E] Distance Sequence

[ABC253E] Distance Sequence

Score : 500500 points

Problem Statement

How many integer sequences A=(A1,,AN)A=(A_1,\ldots,A_N) of length NN satisfy all the conditions below?

  • 1AiM1\le A_i \le M (1iN)(1 \le i \le N)
  • AiAi+1K|A_i - A_{i+1}| \geq K (1iN1)(1 \le i \le N - 1)

Since the count can be enormous, find it modulo 998244353998244353.

Constraints

  • 2N10002 \leq N \leq 1000
  • 1M50001 \leq M \leq 5000
  • 0KM10 \leq K \leq M-1
  • All values in input are integers.

Input

Input is given from Standard Input in the following format:

NN MM KK

Output

Print the count modulo 998244353998244353.

2 3 1
6

The following 66 sequences satisfy the conditions.

  • (1,2)(1,2)
  • (1,3)(1,3)
  • (2,1)(2,1)
  • (2,3)(2,3)
  • (3,1)(3,1)
  • (3,2)(3,2)
3 3 2
2

The following 22 sequences satisfy the conditions.

  • (1,3,1)(1,3,1)
  • (3,1,3)(3,1,3)
100 1000 500
657064711

Print the count modulo 998244353998244353.