N, K = map(int, input().split())
mod = 998244353

def solve(N, K):
    dp = [0] * (K + 2)
    dp[0] = 1
    for _ in range(2 * N):
        dp = [(dp[i - 1] + dp[i + 1]) % mod for i in range(K + 1)] + [0]
    return dp[0]

print((solve(N, K) - solve(N, K - 1)) % mod)