import sys
sys.setrecursionlimit(10**4)
MOD = 998244353
N,K = list(map(int,input().split()))

def f(n,now_depth,MAX_DEPTH):
    if(n == 2*N):return 1 if now_depth == 0 else 0
    if(memo[n][now_depth] != -1):return memo[n][now_depth]
    ret = 0
    # (
    if(now_depth < MAX_DEPTH):ret += f(n+1,now_depth+1,MAX_DEPTH)
    # )
    if(now_depth >= 1):ret += f(n+1,now_depth-1,MAX_DEPTH)

    memo[n][now_depth] = ret % MOD
    return ret % MOD

memo = [[-1 for _ in range(K+1)] for _ in range(2*N)]
ans = f(0,0,K)
memo = [[-1 for _ in range(K+1)] for _ in range(2*N)]
ans -= f(0,0,K-1)
print(ans)