#include <stdio.h>

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

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

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