//https://www.hackerrank.com/challenges/and-product
import java.io.*;

public class Solution {
  public static void main(String[] args) throws IOException {
    StringBuffer sb = new StringBuffer();
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    //For each test
    for(short T = Short.parseShort(br.readLine()); T > 0; --T){

      //Get input
      String[] line = br.readLine().split(" ");
      final long A = Long.parseLong(line[0]);
      final long B = Long.parseLong(line[1]);
      
      //Get output
      long C = B - A;
      for(long t = C; (t = C & (C-1)) > 0; C = t){}
      C = A & B & (-(C << 1));
      
      //Print output
      sb.append(C).append("\n");
    }
    System.out.print(sb);
  }
}

@@ -632,17 +632,16 @@
 A & B & 
-(
 -(C %3C%3C 1
@@ -641,17 +641,16 @@
 (C %3C%3C 1)
-)
 ;%0A      

Update and-product.java