import java.util.*;
import java.lang.*;
import java.io.*;

class Main {
    static String get(int l, int c) {
        if(c>l)
            return "0";
        if(l==0 || c==0)
            return "1";
        
        c=Math.min(c,l-c);
        long res=1;
        //BigInteger bi = new BigInteger("1"); 
        for(long i=0; i<c;i++){
            res = res * (l-i)/(i+1);
            //bi = bi.multiply(BigInteger.valueOf(l-i)).divide(BigInteger.valueOf(i+1));
        }
        return res+"";
        //return bi+"";
	}
    
    public static void main(String[] args) {
        System.out.println(get(4,2)); // "6" 
        System.out.println(get(5,0)); // "1"
        System.out.println(get(67,34)); // "14226520737620288370" : BigInteger
        System.out.println(get(4300,2)); // "9242850"
        System.out.println(get(8000,4000)); // "1550053928509..." : BigInteger
    }
}