#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
#define ll long long
#define all(v) v.begin(),v.end()
#define sz(v) ((ll)v.size())
#define V vector
#define vi V<int>
#define vll V<ll>
#define eb emplace_back
#define pii pair<int,int>
#define pll pair<ll,ll>
#define fi first
#define se second
#define A array
#define pb push_back
#define mset multiset
#define gpumap __gnu_pbds::gp_hash_table
#define ccumap __gnu_pbds::cc_hash_table
#define ui unsigned int
#define ull unsigned ll
#define i128 __int128
#define cerr if (test) cerr
#define freopen if (test) freopen
#define whtest if (test)
using namespace std;

const int test = 0;

namespace jhsy {
	constexpr int P = 998244353;
	ll power(ll b,ll k) {
		ll a = 1;
		for (; k; b = b*b%P, k >>= 1) {
			if (k&1) {
				a = a*b%P;
			}
		}
		return a;
	}
	void main() {
		int n,m;
		cin >> n >> m;
		ll ans = 0;
		for (int i = 0; i < m; i++) {
			ans = (ans+power(m,n)+P-power(m-i,n))%P;
		}
		ans = 2*ans%P;
		ans = (ans+power(m,n))%P;
		cout << ans << '\n';
	}
}

int main() {
	freopen("test.in","r",stdin);
	freopen("test.out","w",stdout);
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout << fixed << setprecision(20);

//	jhsy::init();

	int T = 1;
//	cin >> T;
	while (T--) {
		jhsy::main();
	}

	return 0;
}