#include <stdio.h>

const int Mod = 998244353;

long long div_mod(long long x, long long y, long long z)
{
	if (x % y == 0) return x / y;
	else return (div_mod((1 + x / y) * y - x, (z % y), y) * z + x) / y;
}

int main()
{
	int C, X;
	scanf("%d %d", &C, &X);
	if (X == 0) {
		if (C == 0) printf("1\n");
		else printf("499122177\n");
		fflush(stdout);
		return 0;
	}
	
	int i, j, cur, prev;
	long long dp[2][2003] = {}, inv[2003];
	for (i = 1; i <= X + 1; i++) inv[i] = div_mod(1, i, Mod);
	for (i = C, cur = 1, prev = 0, dp[prev][0] = 1; i < X; i++, cur ^= 1, prev ^= 1) {
		for (j = 0; j <= i; j++) {
			dp[cur][j] += dp[prev][j] * j % Mod * inv[i+1] % Mod;
			dp[cur][j+1] += dp[prev][j] * (i + 1 - j) % Mod * inv[i+1] % Mod;
			dp[prev][j] = 0;
		}
	}
	
	long long ans = 0;
	for (j = 0; j < X; j++) ans += dp[prev][j] * (1 - inv[X+1-j] + Mod) % Mod;
	printf("%lld\n", ans % Mod);
	fflush(stdout);
	return 0;
}