N, K = map(int, input().split())

MOD = 998244353

dp = [[0]*2 for _ in range(K+1)]
dp[0][0] = 1
for _ in range(N*2):
    ndp = [[0]*2 for _ in range(K+1)]
    for i in range(K+1):
        for j in range(2):
            if 1 <= i:
                ndp[i-1][j] += dp[i][j]
                ndp[i-1][j] %= MOD
            if i+1 <= K:
                ndp[i+1][j or i+1==K] += dp[i][j]
                ndp[i+1][j or i+1==K] %= MOD
    dp = ndp

print(dp[0][1])