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]);
        WriteLine((Calc(n * 2, k) - Calc(n * 2, k - 1) + mod) % mod);
    }
    static int mod = 998_244_353;
    static long Calc(int n, int k)
    {
        var dp = new long[k + 1];
        var ndp = new long[k + 1];
        dp[0] = 1;
        for (var i = 0; i < n; ++i)
        {
            for (var j = 0; j < dp.Length; ++j)
            {
                if (j > 0 && j < k) ndp[j] = (dp[j - 1] + dp[j + 1]) % mod;
                else if (j > 0) ndp[j] = dp[j - 1];
                else if (j < k) ndp[j] = dp[j + 1];
                else ndp[j] = 0;
            }
            (dp, ndp) = (ndp, dp);
        }
        return dp[0];
    }
}