import java.math.BigInteger;  
    import java.util.Scanner;  
      
    public class Main{  
        public static void main(String[] args){  
            Scanner scan = new Scanner(System.in);  
            //while(scan.hasNextInt()){  
                int ncase = scan.nextInt();  
                for(int i = 1; i <= ncase; i++){  
                    BigInteger a = scan.nextBigInteger();  
                    BigInteger b = scan.nextBigInteger();
            BigInteger big1 = new BigInteger("1");  
                BigInteger big2 = new BigInteger("2");
            BigInteger big3 = new BigInteger("2"); 
big1=a.subtract(big1);
big2=a.subtract(big2); 
//System.out.println("a:"+big1+" b:"+big2); 
              big1=big1.multiply(big2);
            big1=big1.divide(big3);

            BigInteger result[] = big1.divideAndRemainder(b); 
//System.out.println(big1+" "+b);   
        System.out.println( result[1]);  
                }  
            //}  
        }  
    }