import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int k = sc.nextInt();
		sc.close();

		int mod = 998244353;
		long[] dp = new long[n + 1];
		long[] sum = new long[n + 1];
		dp[0] = 1;
		sum[0] = 1;
		for (int i = 1; i <= n; i++) {
			if (k <= i) {
				dp[i] = sum[i - k];
			}
			sum[i] = sum[i - 1] + dp[i];
			sum[i] %= mod;
		}
		System.out.println(sum[n]);
	}
}