import java.io.PrintWriter
import java.util.*

fun PrintWriter.solve() {
    val n = nextInt()
    val k = nextInt()
    val dp = Array(n + 1) { 1L }
    val mod = 998244353L
    for (i in 1..n) {
        dp[i] = dp[i - 1] + if (i >= k) dp[i - k] else 0
        dp[i] %= mod
    }
    println(dp[n])
}

fun main() {
    val writer = PrintWriter(System.out, false)
    writer.solve()
    writer.flush()
}

// region Scanner
private var st = StringTokenizer("")
private val br = System.`in`.bufferedReader()

fun next(): String {
    while (!st.hasMoreTokens()) st = StringTokenizer(br.readLine())
    return st.nextToken()
}

fun nextInt() = next().toInt()
fun nextLong() = next().toLong()
fun nextLine() = br.readLine()
fun nextDouble() = next().toDouble()
// endregion