//递归做法
#include<stdio.h>
int fun(int m,int n)
{
if(m==0||n==0)
return 1;
else
return fun(m,n-1)+fun(m-1,n);
}
int main()
{
int m,n;
while(scanf("%d%d",&n,&m)!=EOF)
{
printf("%d\n",fun(m,n));
}
}
#include<stdio.h>
int fun(int m,int n)
{
if(m==0||n==0)
return 1;
else
return fun(m,n-1)+fun(m-1,n);
}
int main()
{
int m,n;
while(scanf("%d%d",&n,&m)!=EOF)
{
printf("%d\n",fun(m,n));
}
}