#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <vector>
#include <cstdint>
#include <algorithm>
using namespace std;
using ll = int64_t;
using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int, int>;
using vpii = vector<pair<int, int>>;
const int M = 998244353;
const int N = 2000000;
int sum(int a, int b) {
	if ((a += b) >= M) a -= M;
	return a;
}
int dif(int a, int b) {
	if ((a -= b) < 0) a += M;
	return a;
}
int prod(int a, int b) {
	return ll(a) * b % M;
}
int powmod(int a, int b) {
	int ans = 1;
	while (b) {
		if (b & 1) ans = prod(ans, a);
		b >>= 1;
		a = prod(a, a);
	}
	return ans;
}
int inv(int a, int m) {
	return a == 1 ? 1 : (1 - inv(m % a, a) * ll(m)) / a + m;
}
int factorial(int n, bool inverse) {
	static vi fact, ifact;
	if (fact.empty()) {
		fact.resize(N, 1);
		ifact.resize(N, 1);
		for (int i = 2; i < N; ++i)
			fact[i] = prod(i, fact[i - 1]);
		ifact.back() = inv(fact.back(), M);
		for (int i = N - 1; i >= 3; --i)
			ifact[i - 1] = prod(ifact[i], i);
	}
	return inverse ? ifact[n] : fact[n];
}
namespace FFT {
	struct NTT {
		const int G = 3;
		const int ROOT, size, n;
		vi root, revers, fftA, fftB;
		NTT(const int n = 20) : n(n), size(1 << n), ROOT(powmod(G, (M - 1) >> n)), revers(size), root(size, 1), fftA(size), fftB(size) {
			for (int i = 1; i < size; ++i) root[i] = prod(root[i - 1], ROOT);
		}
		void fft(vi& p, int newN) {
			revers[0] = 0;
			for (int i = 1; i < 1 << newN; ++i) {
				if (i % 2 == 0) revers[i] = revers[i / 2] / 2;
				else revers[i] = revers[i / 2] / 2 + (1 << (newN - 1));
				if (revers[i] < i) swap(p[revers[i]], p[i]);
			}
			for (int l = 1; l <= newN; ++l)
				for (int b = 0; b < (1 << newN - l); ++b)
					for (int step = 0; step < (1 << l - 1); ++step) {
						int n1 = (b << l) + step;
						int n2 = n1 + (1 << l - 1);
						int vA = p[n1];
						int vB = prod(root[step << n - l], p[n2]);
						p[n1] = sum(vA, vB);
						p[n2] = dif(vA, vB);
					}
		}
		void rev_fft(vi& p, int step) {
			fft(p, step);
			reverse(p.begin() + 1, p.begin() + (1 << step));
			int inv_size = inv(1 << step, M);
			for (int i = 0; i < 1 << step; ++i) p[i] = prod(p[i], inv_size);
		}
		template<class Iter>
		vi multiply(Iter Ab, Iter Ae, Iter Bb, Iter Be, int step) {
			if (Ab == Ae || Bb == Be) return {};
			fill(fftA.begin(), fftA.begin() + (1 << step), 0);
			fill(fftB.begin(), fftB.begin() + (1 << step), 0);
			for (auto it = Ab; it != Ae; ++it) fftA[it - Ab] = *it % M;
			for (auto it = Bb; it != Be; ++it) fftB[it - Ab] = *it % M;
			fft(fftA, step);
			fft(fftB, step);
			for (int i = 0; i < (1 << step); ++i) fftA[i] = prod(fftA[i], fftB[i]);
			rev_fft(fftA, step);
			vi result(1 << step);
			copy(fftA.begin(), fftA.begin() + (1 << step), result.begin());
			return result;
		}
		template<class Iter>
		vi power(Iter Ab, Iter Ae, int b, int step) {
			if (Ab == Ae) return {};
			fill(fftA.begin(), fftA.begin() + (1 << step), 0);
			for (auto it = Ab; it != Ae; ++it) fftA[it - Ab] = *it % M;
			fft(fftA, step);
			for (int i = 0; i < (1 << step); ++i) fftA[i] = powmod(fftA[i], b);
			rev_fft(fftA, step);
			vi result(1 << step);
			copy(fftA.begin(), fftA.begin() + (1 << step), result.begin());
			return result;
		}
		vi OGF(vi egf) const {
			int fact = 1, n = egf.size();
			for (int i = 2; i < n; ++i) {
				fact = prod(fact, i);
				egf[i] = prod(egf[i], fact);
			}
			return egf;
		}
	};
}
int find_ans(const int n, const int m) {
	vi poly(m + 1);
	for (int k = 0; k <= m; ++k) {
		poly[k] = prod(factorial(m, false), prod(factorial(m, false), prod(factorial(k, true), prod(factorial(k, true), factorial(m - k, true)))));
		if ((k + m) % 2)
			poly[k] = dif(0, poly[k]);
	}
	FFT::NTT fft;
	vi power_poly = fft.power(poly.begin(), poly.end(), n, 20);
	power_poly = fft.OGF(power_poly);
	int ans = 0;
	for (int i = 0; i <= n * m; ++i)
		ans = sum(ans, power_poly[i]);
	return ans;
}
bool solve_test() {
	int n, m;
	if (!(cin >> n >> m)) return false;
	cout << find_ans(n, m) << '\n';
	return true;
}

int main() {
#ifdef HOME
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif
	while (solve_test());
}