#pragma GCC optimize("Ofast,unroll-loops")
#include <stdio.h>

const int Mod = 998244353;

int main()
{
	int N, M;
	scanf("%d %d", &N, &M);
	
	int i, j, k, cur, prev, dp[2][1003][1003] = {};
	dp[0][0][0] = 2;
	for (i = 2, cur = 1, prev = 0; i <= N; i++, cur ^= 1, prev ^= 1) {
		for (j = (i - 1 < M)? i - 1: M; j > 0; j--) {
			for (k = 0; k <= M; k++) {
				if (j == M) dp[cur][j][k] = dp[prev][j-1][k];
				else {
					dp[cur][j][k] = dp[cur][j+1][k] + dp[prev][j-1][k] - dp[prev][j][k];
					if (dp[cur][j][k] >= Mod) dp[cur][j][k] -= Mod;
					else if (dp[cur][j][k] < 0) dp[cur][j][k] += Mod;
				}
			}
			for (k = j; k <= M; k++) {
				dp[cur][j][k] += dp[prev][j][k-j];
				if (dp[cur][j][k] >= Mod) dp[cur][j][k] -= Mod;
			}
			if (j == i - 1) dp[cur][j][j]++;
		}
		for (k = 0; k <= M; k++) {
			dp[cur][0][k] = dp[cur][1][k] * 2;
			if (dp[cur][0][k] >= Mod) dp[cur][0][k] -= Mod;
		}
	}
	printf("%d\n", dp[prev][0][M]);
	fflush(stdout);
	return 0;
}