#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
using mint = modint998244353;
const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
// combination mod prime
// https://www.youtube.com/watch?v=8uowVvQ_-Mo&feature=youtu.be&t=1619
struct combination {
	vector<mint> fact, ifact;
	combination(int n) :fact(n + 1), ifact(n + 1) {
		assert(n < mod);
		fact[0] = 1;
		for (int i = 1; i <= n; ++i) fact[i] = fact[i - 1] * i;
		ifact[n] = fact[n].inv();
		for (int i = n; i >= 1; --i) ifact[i - 1] = ifact[i] * i;
	}
	mint operator()(int n, int k) { return com(n, k); }
	mint com(int n, int k) {
		//負の二項係数を考慮する場合にコメントアウトを外す
		//if (n < 0) return com(-n, k) * (k % 2 ? -1 : 1);
		if (k < 0 || k > n) return 0;
		return fact[n] * ifact[k] * ifact[n - k];
	}
	mint inv(int n, int k) {
		//if (n < 0) return inv(-n, k) * (k % 2 ? -1 : 1);
		if (k < 0 || k > n) return 0;
		return ifact[n] * fact[k] * fact[n - k];
	}
	mint p(int n, int k) { return fact[n] * ifact[n - k]; }
}c(200005);
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n, m; cin >> n >> m;
	int maxmex = min(n, m + 1);
	//dp[i][j]:=長さがjで[0,i)で構成されたmexがiの数列の数
	vector<vector<mint>> dp(maxmex + 1, vector<mint>(n + 1));
	dp[0][0] = 1;
	rep(i, maxmex) {
		vector<mint>x = dp[i];
		rep(j, x.size())x[j] *= c.ifact[j];
		vector<mint>y(n + 1);
		rep2(j, 1, y.size())y[j] = c.ifact[j];
		auto z = convolution(x, y);
		rep(j, n + 1)dp[i + 1][j] = z[j] * c.fact[j];
	}
	/*rep(i, maxmex + 1) {
		rep(j, n + 1) cout << dp[i][j].val() << " ";
		cout << endl;
	}*/

	//dp2[i][j]:=長さがjでmexがiの数列の数
	vector<vector<mint>> dp2(maxmex + 1, vector<mint>(n + 1));
	rep(i, maxmex + 1) {
		vector<mint>x(n + 1);
		rep(j, n + 1)x[j] = c.ifact[j] * pow_mod(max(0, m - i), j, mod);
		vector<mint>y = dp[i];
		rep(j, y.size())y[j] *= c.ifact[j];
		auto z = convolution(x, y);
		rep(j, n + 1)dp2[i][j] = z[j] * c.fact[j];
		/*cout << endl;
		rep(j, x.size()) cout << x[j].val() << " ";
		cout << endl;
		rep(j, y.size()) cout << y[j].val() << " ";
		cout << endl;
		rep(j, z.size()) cout << z[j].val() << " ";
		cout << endl;*/
	}
	/*rep(i, maxmex + 1) {
		rep(j, n + 1) cout << dp2[i][j].val() << " ";
		cout << endl;
	}*/







	mint ans = 0;
	/*rep2(i, 1, n + 1) {//数列の長さ
		rep(j, maxmex + 1) {//mex
			rep(k, i + 1) {//以下の数。
				if ((m - j < 0) && (i - k > 0))continue;
				ans += c(n, i) * pow_mod(m + 1, n - i, mod)*j * dp[j][k] * c(i, k)*pow_mod(m - j, i - k, mod);
			}
		}
	}*/
	rep2(i, 1, n + 1) {
		rep(j, maxmex + 1)ans += c(n, i) * pow_mod(m + 1, n - i, mod) * dp2[j][i] * j;
	}
	cout << ans.val() << endl;
	return 0;
}