package main

import . "fmt"

func main() {
	var n, k int
	Scan(&n, &k)
	ans := solve(n, k)
	Println(ans)
}

func solve(n, k int) int {
	if k > n {
		return 1
	}
	const MOD = 998244353
	dp1 := 0
	dp2 := make([]int, n+1)
	dp2[0] = 1
	ans := 1
	for i := k; i <= n; i++ {
		dp1 = (dp1+dp2[i-k])%MOD
		dp2[i] = dp1
		ans = (ans+dp1)%MOD
	}
	return ans
}

func init() {
	for n := 1; n <= 300; n++ {
		for k := 1; k <= n; k++ {
			sa := solve(n, k)
			ha := hoge(n, k)
			if sa != ha {
				panic(Sprintf("n=%d,k=%d,sa=%d,ha=%d",n,k,sa,ha))
			}
		}
	}
}

func hoge(n, k int) int {
	if k > n {
		return 1
	}
	const MOD = 998244353
	// reference: https ://cp-algorithms.com/data_structures/fenwick.html#3-range-update-and-range-query
	b1 := make([]int, n+3)
	b2 := make([]int, n+3)
	add := func(b []int, idx, x int) {
		for x < 0 {
			x += (-x+MOD-1)/MOD*MOD
		}
		for idx < len(b) {
			b[idx] = (b[idx]+x)%MOD
			idx += idx & -idx
		}
	}
	rangeAdd := func(l, r, x int) {
		add(b1, l, x)
		add(b1, r+1, -x)
		add(b2, l, x*(l-1))
		add(b2, r+1, -x*r)
	}
	sum := func(b []int, idx int) int {
		total := 0
		for idx > 0 {
			total = (total + b[idx])%MOD
			idx -= idx & -idx
		}
		return total
	}
	prefixSum := func(idx int) int {
		return (sum(b1, idx)*idx - sum(b2, idx))%MOD
	}
	rangeSum := func(l, r int) int {
		return (prefixSum(r) - prefixSum(l-1))%MOD
	}
	rangeAdd(1, 1, 1)
	for i := 1; i+k <= n+1; i++ {
		x := rangeSum(i, i)
		rangeAdd(i+k, n+1, x)
	}
	ans := rangeSum(1, n+1)
	for ans < 0 {
		ans += (-ans+MOD-1)/MOD*MOD
	}
	return ans
}