#include <bits/stdc++.h>

using namespace std;
using ll = long long;

constexpr ll mod = 998244353;

ll modPow(ll x, ll n) {
    if (!n)return 1;
    ll u = modPow(x, n / 2);
    u = u * u % mod;
    if (n % 2)u = u * x % mod;
    return u;
}

int main() {
    cin.tie(0)->sync_with_stdio(false);
    ll n, m;
    cin >> n >> m;

    ll res = modPow(m, n);
    for (ll x = 0; x < m; ++x) {
        (res += 2*(modPow(m, n) - modPow(x + 1, n))) %= mod;
    }
    if (res < 0)res += mod;
    cout << res;
}