UVA - 369 - Combinations

import java.io.IOException;
import java.math.BigInteger;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) throws IOException {
        Scanner s=new Scanner(System.in);
        StringBuffer sb = new StringBuffer("");
        BigInteger[] fact=new BigInteger[101];
        fact[0]=BigInteger.ONE;
         for (int i=1; i < 101; i++) {
            fact[i]=fact[i-1].multiply(BigInteger.valueOf(i));
        }
       while(true) {
            int n=s.nextInt();
            int m=s.nextInt();
            if(n==0 && m==0)
                break;
            BigInteger ans=fact[n].divide((fact[n-m]).multiply(fact[m]));
            sb.append(n).append(" things taken ").append(m).append(" at a time is ").append(ans).append(" exactly.\n");
        }
        System.out.print(sb);
    }
}