/* -*- coding: utf-8 -*-
 *
 * 3213.cc:  No.3213 depth max K - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 5000;
const int MAX_N2 = MAX_N * 2;
const int MOD = 998244353;

/* typedef */

/* global variables */

int dp0[MAX_N2 + 1][MAX_N + 1], dp1[MAX_N2 + 1][MAX_N + 1];

/* subroutines */

inline void addmod(int &a, int b) { a = (a + b) % MOD; }

/* main */

int main() {
  int n, k;
  scanf("%d%d", &n, &k);
  int n2 = n * 2;

  dp0[0][0] = 1;
  for (int i = 0; i < n2; i++)
    for (int j = 0; j <= k; j++) {
      if (dp0[i][j]) {
	if (j == k - 1)
	  addmod(dp1[i + 1][j + 1], dp0[i][j]);
	else if (j < k)
	  addmod(dp0[i + 1][j + 1], dp0[i][j]);
	if (j > 0)
	  addmod(dp0[i + 1][j - 1], dp0[i][j]);
      }
      if (dp1[i][j]) {
	if (j < k)
	  addmod(dp1[i + 1][j + 1], dp1[i][j]);
	if (j > 0)
	  addmod(dp1[i + 1][j - 1], dp1[i][j]);
      }
    }

  printf("%d\n", dp1[n2][0]);
  
  return 0;
}