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

//*
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
// using mint = modint1000000007;
//*/

using ll = long long;
using i128 = __int128_t;
using pll = pair<ll, ll>;
using tlll = tuple<ll, ll, ll>;
using ld = long double;
const int INF = 1000100100;
const ll INFF = 1000100100100100100LL;
const int dx[4] = {0, 0, 1, -1}, dy[4] = {1, -1, 0, 0};
#define overload4(_1, _2, _3, _4, name, ...) name
#define rep1(i, n) for (ll i = 0; i < ll(n); i++)
#define rep2(i, l, r) for (ll i = ll(l); i < ll(r); i++)
#define rep3(i, l, r, d) for (ll i = ll(l); (d) > 0 ? i < ll(r) : i > ll(r); i += d)
#define rep(...) overload4(__VA_ARGS__, rep3, rep2, rep1)(__VA_ARGS__)
#define per(i, n) for (int i = (n) - 1; i >= 0; --i)
#define yesno(f) cout << (f ? "Yes" : "No") << endl;
#define YESNO(f) cout << (f ? "YES" : "NO") << endl;
#define all(a) (a).begin(), (a).end()
#define popc(x) __builtin_popcountll(ll(x))

template <typename S, typename T>
ostream &operator<<(ostream &os, const pair<S, T> &p) {
    return os << p.first << ' ' << p.second;
}

template <typename T>
void printvec(const vector<T> &v) {
    int n = v.size();
    rep(i, n) cout << v[i] << (i == n - 1 ? "" : " ");
    cout << '\n';
}

template <typename T>
void printvect(const vector<T> &v) {
    for (auto &vi : v) cout << vi << '\n';
}

template <typename T>
void printvec2(const vector<vector<T>> &v) {
    for (auto &vi : v) printvec(vi);
}

template <typename S, typename T>
bool chmax(S &x, const T &y) {
    return (x < y) ? (x = y, true) : false;
}

template <typename S, typename T>
bool chmin(S &x, const T &y) {
    return (x > y) ? (x = y, true) : false;
}

#ifdef LOCAL  // https://zenn.dev/sassan/articles/19db660e4da0a4
#include "cpp-dump-main/dump.hpp"
#define dump(...) cpp_dump(__VA_ARGS__)
CPP_DUMP_DEFINE_DANGEROUS_EXPORT_OBJECT(val());
#else
#define dump(...)
#endif

struct io_setup {
    io_setup() {
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
    }
} io_setup;
void solve() {
    ll n, m;
    cin >> n >> m;
    mint ans = mint(m).pow(n) * n;

    rep(i, 2, m + 1) {
        mint res = mint(m + 1 - i) / m;
        ans += mint(m).pow(n) * (m + 1 - i) / (i - 1) * (1 - mint(res).pow(n));
    }
    cout << ans.val() << endl;
}
int main() {
    int t;
    // cin >> t;
    t = 1;
    while (t--) {
        solve();
    }
}