#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define fin  "1-sir.in"
#define fout "1-sir.out"
int n,s,sol,x[1000];
FILE *in,*out;

void go(int p,int sum,int el) {
int i,tmp;
	
	if (sum>s) return; 

	if (p==n+1) {  if (sum==s) {
				//for (i=1;i<=n;++i) printf("%i ",x[i]);	
				//printf("\n");
				sol++; } 
	}
	
	else {
		tmp=el+1;
		//x[p]=tmp;
		go(p+1,sum+tmp,tmp);
		tmp=el-1;
		//x[p]=tmp;
		go(p+1,sum+tmp,tmp);
	}
}

int main() {
	in=fopen(fin,"r"); out=fopen(fout,"w");
	fscanf(in,"%i%i",&n,&s);
	go(2,0,0);
	fprintf(out,"%i\n",sol);
	
	fclose(in); fclose(out);

	return 0;
}