using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
using System.Runtime.Intrinsics.Arm;

class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, k) = ((int)c[0], c[1]);
        var a = new long[1][];
        a[0] = new long[n * 4 + 2];
        a[0][0] = 1;
        var x = new long[n * 4 + 2][];
        for (var i = 0; i < n * 4 + 2; ++i)
        {
            x[i] = new long[n * 4 + 2];
            if (i == n * 4)
            {
                x[i][i + 1] = 5;
            }
            else if (i == n * 4 + 1)
            {
                x[i][i] = 5;
            }
            else
            {
                if (i % 4 == 0)
                {
                    x[i][0] = 4;
                    x[i][i + 1] = 1;
                }
                else
                {
                    x[i][0] = 3;
                    x[i][1] = 1;
                    x[i][i + 1] = 1;
                }
            }
        }
        for (var i = 0; i < x.Length; ++i) for (var j = 0; j < x[i].Length; ++j) x[i][j] = x[i][j] * rev % mod;
        var b = Mul(a, Pow(x, k));
        WriteLine(b[0][n * 4]);
    }
    static int mod = 998_244_353;
    static int rev = 598_946_612;
    // 行列の累乗
    public static long[][] Pow(long[][] m, long k)
    {
        var multi = m;
        var r = new long[m.Length][];
        for (var i = 0; i < m.Length; ++i)
        {
            r[i] = new long[m.Length];
            r[i][i] = 1;
        }
        while (k > 0)
        {
            if ((k & 1) == 1) r = Mul(r, multi);
            multi = Mul(multi, multi);
            k >>= 1;
        }
        return r;
    }
    // 行列の積
    public static long[][] Mul(long[][] x, long[][] y)
    {
        var r = new long[x.Length][];
        for (var i = 0; i < x.Length; ++i) r[i] = new long[y[0].Length];
        for (var i = 0; i < x.Length; ++i) for (var k = 0; k < x[0].Length; ++k)
        {
            for (var j = 0; j < y[0].Length; ++j) r[i][j] = (r[i][j] + x[i][k] * y[k][j]) % mod;
        }
        return r;
    }
}