#include <stdio.h>

int com(int n, int r)
{
	if(n==r || r==0)
		return 1;
	else
		return com(n-1, r-1)+com(n-1, r);
}

int path(int x, int y)
{
	if(x==0 && y==0)
		return 0;
	else 
		return com(x+y,y);
}

int main(void) {
	int x,y;
	
	scanf("%d %d",&x,&y);
	
	printf("%d\n",path(x,y));
	
	return 0;
}