> #include <iostream>
> using namespace std;
> int main()
> {
>     long long n,k;
>     while(cin>>n>>k)
>     {
>       if(n==0&&k==0)
>        break;
>       __int64 answer=1;
>       __int64 mol=1;
>       __int64 den=1;
>       if(k==0||k==n)
>          ;
>       else
>       {
>        if(k>n/2)
>          k=n-k;
>        for(int i=0;i<k;++i)
>        {
>               mol*=(n-i);
>               den*=(i+1);
>        }
>        answer=mol/den;
>       }
>       printf("%I64d\n",answer);
>     }
> }
>       
>       
>     
>