## https://yukicoder.me/problems/no/2791

MOD = 998244353

def main():
    N, K = map(int, input().split())

    dp = [0] * (N + 1)
    dp[0] = 1

    c = 0
    for k in range(N + 1):
        if k > 0:
            c += dp[k]
            c %= MOD
            dp[k] = c

        if k + K <= N:
            dp[k + K] += dp[k]
            dp[k + K] %= MOD

    answer = 0
    for ik in range(N + 1):
        answer += dp[ik]
        answer %= MOD
    print(answer)



if __name__ == "__main__":
    main()