#include <bits/stdc++.h>
using namespace std;
long double func_tion (long double n)
{
long double i,r = 1;
for ( i = 2; i <= n; i++)
{
r *= i;
}
return r;
}
int main ()
{
long double M, N,r,n,m;
while (cin>>N>>M)
{
if( N==0 and M==0 ) break;
n=(func_tion(N));
m=(func_tion(N-M)*func_tion(M));
r = n/m;
cout << N << " things taken " << M << " at a time is " << setprecision(0) << r << " exactly." << endl;
}
return 0;
}