ACM Q530

import java.util.Scanner;
public class Main {
  public static void main(String args[]) {
    Scanner cin = new Scanner(System.in);
    while(cin.hasNextDouble() ){
      double n = cin.nextDouble();
      double m = cin.nextDouble();
      double fac_n=1, fac_m=1;
      double count;
      if(n<1&&m==0&&m-n<=0){
      break;
      }
      if(m==0){
      System.out.println(1);
      continue;
      }
      if(n-m < m){
      count = n-m;
      }else{
      count =m;
      }
      for(double i=0; i<count; i++){
        fac_n *= (n-i);
      }
      for(double j=1; j<=count; j++){
        fac_m *= j;
      }
      System.out.println((int) (fac_n / fac_m));
    }
  }
}