using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, k) = (c[0], c[1]);
        var mod = 998_244_353;
        var dp = new long[n + 1];
        dp[0] = 1;
        var add = new long[n + 1];
        for (var i = 0; i <= n; ++i)
        {
            if (i > 0) add[i] = (add[i] + add[i - 1]) % mod;
            dp[i] = (dp[i] + add[i]) % mod;
            if (i + k <= n) add[i + k] = (add[i + k] + dp[i]) % mod;
        }
        WriteLine(dp.Sum() % mod);
    }
}