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

const ll mod = 998244353;

ll modpow(ll a, ll b){
	if(b == 0)return 1;
	if(b % 2 == 0){
		ll t = modpow(a, b/2);
		t *= t;
		t %= mod;
		return t;
	}
	ll ret = a % mod;
	ret *= modpow(a, b-1);
	ret %= mod;
	return ret;
}

int main(){
	ll N, M; cin >> N >> M;
	ll ans = 0;
	for(ll y = 1; y <= M; y++){
		ll add = modpow(M, N) - modpow(y, N);
		while(add < 0)add += mod;
		add %= mod;
		ans += add;
		ans %= mod;
	}
	ans *= 2;
	ans %= mod;
	ans += modpow(M, N);
	ans %= mod;
	cout << ans << endl;
	return 0;
}