#include<stdio.h>
int n, k;
int f(int a, int b, int d){
	if(a==n and b == n and d<=k) return 1;
	if(a>=n or b >= n or d>=k) return 0;
	return f(a+1,b+1,d+1)+f(a+1,b+2,d+1)+f(a+2,b+1,d+1)+f(a+2,b+2,d+1);
}
int main(){
	scanf("%d %d", &n, &k);
	printf("%d",f(0, 0, 1));
}