#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;

using Mint = atcoder::modint998244353;

struct Mat
{
    Mint A[3][3];
};

Mat mul(Mat a, Mat b)
{
    Mat c;
    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++)
            for (int k = 0; k < 3; k++)
                c.A[i][j] += a.A[i][k] * b.A[k][j];
    return c;
}

Mat pow(Mat a, int x)
{
    if (x == 1)
        return a;
    auto ret = pow(a, x / 2);
    ret = mul(ret, ret);
    if (x & 1)
        ret = mul(ret, a);
    return ret;
}

int main()
{
    int N, K;
    cin >> N >> K;
    Mint ans = 0;
    for (int x = 1; x <= K; x++)
    {
        Mat A;
        A.A[0][0] = K;
        A.A[0][1] = K - (x - 1);
        A.A[1][1] = x - 1;
        A.A[1][2] = K - (x - 1);
        A.A[2][2] = x - 1;
        A = pow(A, N);

        ans += A.A[0][2];
    }
    cout << ans.val() << endl;
}