#include <cstdio>
using namespace std;
int a,b,c,d,f[201][20002];
int main(void)
{
	freopen ("empire.in","r",stdin);
	freopen ("empire.out","w",stdout);
	scanf("%d%d",&a,&b);
	f[1][1]=1;
	for (c=1;c<=a*2-1;c++) f[c][0]=1;
	for (c=2;c<=a*2-1;c++)
		for (d=1;d<=b;d++)
			if (d>c) f[c][d]=0;
				else f[c][d]=(f[c-1][d]+f[c-1][d-1]*((c-1)/2*2+1-d+1))%504;
	printf("%d",f[a*2-1][b]);
	fclose(stdin);
	fclose(stdout);
	return 0;
}