import sys
sys.setrecursionlimit(10**7)
from functools import lru_cache

MOD = 998244353

def main():
    N, K = map(int, sys.stdin.readline().split())

    @lru_cache(maxsize=None)
    def f(i: int) -> int:
        if i == 0:
            return 1
        if i < K:
            return 0
        return S(i - K) % MOD  # 漸化式 f(i) = S(i-K)

    @lru_cache(maxsize=None)
    def S(x: int) -> int:
        if x < 0:
            return 0
        return (S(x - 1) + f(x)) % MOD  # 累積和

    # 答えは S(N)
    print(S(N) % MOD)

if __name__ == "__main__":
    main()