#include <bits/stdc++.h>

using namespace std;

const int INF = 998244353;
const int maxn = 1e6 + 5;

inline int qpow(int x, int y) {
	int ret = 1;
	for (; y; y >>= 1) {
		// printf("y = %d\n", y);
		if (y & 1) ret = 1ll * ret * x % INF;
		x = 1ll * x * x % INF;
	}
	return ret;
}

int n, m;

int main(){
	scanf("%d%d", &n, &m);
	int ans = 0;
	
	int shit = 0, shit2 = 0;
	
	for (int y = 1; y <= m; ++y) {
		ans = (ans + 2ll * (qpow(m, n) + INF - qpow(m - y, n))) % INF;
	}
	
	
	/*
	for (int k = 0; k <= n; ++k) {
		int tot = 0;
		for (int x = 1; x <= m; ++x) {
			int sum = 0, res = 0;
			res = (qpow(x, k) + INF - qpow(x - 1, k)) % INF;
			for (int y = x; y <= m; ++y) {
				(sum += qpow(m - y, n - k)) %= INF;
			}
			sum = 2ll * sum % INF;
			printf("k = %d x = %d sum = %d\n", k, x, sum);
			tot = (tot + 1ll * res * sum) % INF;
		}
		printf("k = %d tot = %d\n", k, tot);
		ans = (ans + 1ll * binom(n, k) * tot) % INF;
	}
	*/
	
	
	for (int x = 1; x <= m; ++x) {
		int res = (2ll * (m - x) + 1) * (qpow(x, n) + INF - qpow(x - 1, n)) % INF;
		shit2 = (shit2 + INF - res) % INF;
	}
	ans = (ans + shit2) % INF;
	
	for (int y = 1; y <= m; ++y) ans = (ans + 2ll * qpow(m - y, n)) % INF;
	
	
	// printf("shit = %d shit2 = %d\n", shit, shit2);
	
	printf("%d\n", ans);
	return 0;
}