import java.io.*;

 import java.util.*;

 import java.math.*;

 class Main

 {

     public static void main(String[] args)

     {

         Scanner sc = new Scanner(System.in);

         BigInteger[] fact = new BigInteger[110];

         fact[0] = BigInteger.ONE;

         for (int i = 1; i <= 100; i++)

             fact[i] = fact[i-1].multiply(BigInteger.valueOf(i));

         int n, m;

         while (sc.hasNext())

         {

             n = sc.nextInt();

             m = sc.nextInt();

             if (n == 0 && m == 0)  break;

             BigInteger ans = fact[n].divide(fact[m]).divide(fact[n-m]);

             System.out.println(n + " things taken " + m + " at a time is " + ans + " exactly.");

         }

     }

 }