import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
long c;
    public static void main(String[] args) throws IOException{
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        
        BufferedReader in=new BufferedReader (new InputStreamReader (System.in));
        
       String s=in.readLine();
        
        String[] st= new String [10];
        
        long n=Long.parseLong(s);
        long[] ele =new long[10];
        long ans=0;
        for (int i=0;i<n;i++){
            
            s=in.readLine();
            st=s.split(" ");
            ele[0]=Long.parseLong(st[0]);
             ele[1]=Long.parseLong(st[1]);
            long diff=ele[0]-ele[1]+1;
            if(diff>=ele[1]){
                 ans= fact(diff)/(fact(ele[1])*fact(diff-ele[1]));}
            else { ans=0;}
            System.out.println(ans);
        }
    }
    
    
    public static long fact(long a){
        
      if (a==0){return 1;}
        else {
           return a*fact(a-1);
        }
    }
}