from collections import *
import sys
import heapq
import bisect
import itertools
from functools import lru_cache
from types import GeneratorType
from fractions import Fraction
import math
import copy
import random

# sys.setrecursionlimit(int(1e7))
# @lru_cache(maxsize=None) # CPython特化
# @bootstrap # PyPy特化(こっちのほうが速い) yield dfs(), yield Noneを忘れずに


def bootstrap(f, stack=[]):  # yield
    def wrappedfunc(*args, **kwargs):
        if stack:
            return f(*args, **kwargs)
        else:
            to = f(*args, **kwargs)
            while True:
                if type(to) is GeneratorType:
                    stack.append(to)
                    to = next(to)
                else:
                    stack.pop()
                    if not stack:
                        break
                    to = stack[-1].send(to)
            return to

    return wrappedfunc


dxdy1 = ((0, 1), (0, -1), (1, 0), (-1, 0))  # 上下右左
dxdy2 = (
    (0, 1),
    (0, -1),
    (1, 0),
    (-1, 0),
    (1, 1),
    (-1, -1),
    (1, -1),
    (-1, 1),
)  # 8方向すべて
dxdy3 = ((0, 1), (1, 0))  # 右 or 下
dxdy4 = ((1, 1), (1, -1), (-1, 1), (-1, -1))  # 斜め
INF = float("inf")
_INF = 1 << 60
MOD = 998244353
mod = 998244353
MOD2 = 10**9 + 7
mod2 = 10**9 + 7
# memo : len([a,b,...,z])==26
# memo : 2^20 >= 10^6
# 小数の計算を避ける : x/y -> (x*big)//y  ex:big=10**9
# @:小さい文字, ~:大きい文字,None: 空の文字列
# ユークリッドの互除法：gcd(x,y)=gcd(x,y-x)
# memo : d 桁以下の p 進表記を用いると p^d-1 以下のすべての
#        非負整数を表現することができる
# memo : (X,Y) -> (X+Y,X−Y) <=> 点を原点を中心に45度回転し、√2倍に拡大
# memo : (x,y)のx正から見た偏角をラジアンで(-πからπ]：　math.atan2(y, x)
# memo : a < bのとき ⌊a⌋ ≦ ⌊b⌋

input = lambda: sys.stdin.readline().rstrip()
mi = lambda: map(int, input().split())
li = lambda: list(mi())
ii = lambda: int(input())
py = lambda: print("Yes")
pn = lambda: print("No")
pf = lambda: print("First")
ps = lambda: print("Second")


# ACLのではない。機能は減るが、こっちのほうが早い
class LazySegTree:
    def __init__(self, v, op, e, mapping, composition, id_):
        n = len(v)
        self._op = op
        self._e = e
        self._mapping = mapping
        self._composition = composition
        self._id = id_
        self._size = 1 << (n - 1).bit_length()
        self._d = [e] * (2 * self._size)
        self._lz = [id_] * 2 * self._size
        for i in range(n):
            self._d[self._size + i] = v[i]
        for i in range(self._size - 1, 0, -1):
            self._d[i] = self._op(self._d[2 * i], self._d[2 * i + 1])

    def _gindex(self, l, r):
        l += self._size
        r += self._size
        lm = l >> (l & -l).bit_length()
        rm = r >> (r & -r).bit_length()
        while r > l:
            if l <= lm:
                yield l
            if r <= rm:
                yield r
            l >>= 1
            r >>= 1
        while l:
            yield l
            l >>= 1

    def _propagates(self, *ids):
        for i in reversed(ids):
            f = self._lz[i]
            self._lz[i] = self._id
            self._lz[2 * i] = self._composition(f, self._lz[2 * i])
            self._lz[2 * i + 1] = self._composition(f, self._lz[2 * i + 1])
            self._d[2 * i] = self._mapping(f, self._d[2 * i])
            self._d[2 * i + 1] = self._mapping(f, self._d[2 * i + 1])

    def apply(self, l, r, f):
        (*ids,) = self._gindex(l, r)
        self._propagates(*ids)
        l += self._size
        r += self._size
        while l < r:
            if l & 1:
                self._lz[l] = self._composition(f, self._lz[l])
                self._d[l] = self._mapping(f, self._d[l])
                l += 1
            if r & 1:
                self._lz[r - 1] = self._composition(f, self._lz[r - 1])
                self._d[r - 1] = self._mapping(f, self._d[r - 1])
            l >>= 1
            r >>= 1
        for i in ids:
            self._d[i] = self._op(self._d[2 * i], self._d[2 * i + 1])

    def prod(self, l, r):
        self._propagates(*self._gindex(l, r))
        resl = self._e
        resr = self._e
        l += self._size
        r += self._size
        while l < r:
            if l & 1:
                resl = self._op(resl, self._d[l])
                l += 1
            if r & 1:
                resr = self._op(self._d[r - 1], resr)
            l >>= 1
            r >>= 1
        return self._op(resl, resr)


# RMQのとき
def op(a, b):
    return (a + b) % MOD


def mapping(f, x):  # 更新(dataに作用, fは上書きフラグ(f==ID: False))
    return (f + x) % MOD


def composition(
    f, g
):  # 更新(lazyに作用, fは上書きフラグ(f==ID: False), 作用順はg→f, fは新しく入ってきたやつ)
    return (f + g) % MOD


ini = 0
ID = ini
e = ini
N, K = mi()
dp = LazySegTree([ini] * (N + 1), op, e, mapping, composition, ID)
dp.apply(0, 1, 1)
for i in range(N):
    if i + K <= N:
        dp.apply(i + K, N + 1, dp.prod(i, i + 1))
print(dp.prod(0, N + 1))