#include <iostream>

#include <cstdio>

#define REP(i,a,n) for(int i=a;i<=n;++i)

using namespace std;

typedef long long ll;

const int N = 2e3+10, P = 998244353;

int n, d, dp[N][N], fac[N][N];

int main() {

	dp[0][0] = 1;

	REP(i,0,2000) REP(j,0,i/2) if (dp[i][j]) {

		int &r = dp[i][j];

		if (i&1) {

			dp[i+1][j] = (dp[i+1][j]+(ll)(i+1-j-2)*r)%P;

			dp[i+1][j+1] = (dp[i+1][j+1]+2ll*r)%P;

			if (j) dp[i+1][j-1] = (dp[i+1][j-1]+(ll)j*r)%P;

		}

		else {

			dp[i+1][j] = (dp[i+1][j]+(ll)(i+1-j)*r)%P;

			if (j) dp[i+1][j-1] = (dp[i+1][j-1]+(ll)j*r)%P;

		}

	}

	REP(i,1,1000) {

		fac[i][0] = 1;

		REP(j,1,1000) fac[i][j] = (ll)fac[i][j-1]*i%P;

	}

	while (~scanf("%d%d", &n, &d)) {

		int ans = 0;

		REP(i,0,n) {

			ans = (ans+(ll)dp[2*n][i]*fac[d][i])%P;

		}

		printf("%d\n", ans);

	}

}