description: Alice gave Bob two integers a and b (a > 0 and b ≥ 0). Being a curious boy, Bob wrote down an array of non-negative integers with \operatorname{MEX} value of all elements equal to a and \operatorname{XOR} value of all elements equal to b.
  
  What is the shortest possible length of the array Bob wrote?
  
  Recall that the \operatorname{MEX} (Minimum EXcluded) of an array is the minimum non-negative integer that does not belong to the array and the \operatorname{XOR} of an array is the [bitwise XOR](https://en.wikipedia.org/wiki/Bitwise_operation#XOR) of all the elements of the array.
  
  Input
  
  The input consists of multiple test cases. The first line contains an integer t (1 ≤ t ≤ 5 ⋅ 10^4) — the number of test cases. The description of the test cases follows.
  
  The only line of each test case contains two integers a and b (1 ≤ a ≤ 3 ⋅ 10^5; 0 ≤ b ≤ 3 ⋅ 10^5) — the \operatorname{MEX} and \operatorname{XOR} of the array, respectively.
  
  Output
  
  For each test case, output one (positive) integer — the length of the shortest array with \operatorname{MEX} a and \operatorname{XOR} b. We can show that such an array always exists.
  
  Example
  
  Input
  
  
  5
  1 1
  2 1
  2 0
  1 10000
  2 10000
  
  
  Output
  
  
  3
  2
  3
  2
  3
  
  Note
  
  In the first test case, one of the shortest arrays with \operatorname{MEX} 1 and \operatorname{XOR} 1 is [0, 2020, 2021].
  
  In the second test case, one of the shortest arrays with \operatorname{MEX} 2 and \operatorname{XOR} 1 is [0, 1].
  
  It can be shown that these arrays are the shortest arrays possible.
solution: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.util.InputMismatchException;
  import java.io.IOException;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author dauom
   */
  public class Main {
    public static void main(String[] args) {
      InputStream inputStream = System.in;
      OutputStream outputStream = System.out;
      InputReader in = new InputReader(inputStream);
      PrintWriter out = new PrintWriter(outputStream);
      BMEXorMixup solver = new BMEXorMixup();
      solver.solve(1, in, out);
      out.close();
    }
  
    static class BMEXorMixup {
      private static final int MAXN = (int) 3e5 + 5;
  
      public final void solve(int testNumber, InputReader in, PrintWriter out) {
        int[] xor = new int[MAXN];
        for (int i = 1; i < MAXN; i++) {
          xor[i] = i ^ xor[i - 1];
        }
  
        int t = in.nextInt();
        while (t-- > 0) {
          final int a = in.nextInt();
          final int b = in.nextInt();
          int xa = xor[a - 1];
          int ans = a;
          int cur = a + 1;
          while (xa != b) {
            ++ans;
            int target = xa ^ b;
            if (target == a) {
              xa ^= cur++;
            } else {
              break;
            }
          }
          out.println(ans);
        }
      }
  
    }
  
    static final class InputReader {
      private final InputStream stream;
      private final byte[] buf = new byte[1 << 18];
      private int curChar;
      private int numChars;
  
      public InputReader() {
        this.stream = System.in;
      }
  
      public InputReader(final InputStream stream) {
        this.stream = stream;
      }
  
      private int read() {
        if (this.numChars == -1) {
          throw new UnknownError();
        } else {
          if (this.curChar >= this.numChars) {
            this.curChar = 0;
  
            try {
              this.numChars = this.stream.read(this.buf);
            } catch (IOException ex) {
              throw new InputMismatchException();
            }
  
            if (this.numChars <= 0) {
              return -1;
            }
          }
  
          return this.buf[this.curChar++];
        }
      }
  
      public final int nextInt() {
        int c;
        for (c = this.read(); isSpaceChar(c); c = this.read()) {
        }
  
        byte sgn = 1;
        if (c == 45) { // 45 == '-'
          sgn = -1;
          c = this.read();
        }
  
        int res = 0;
  
        while (c >= 48 && c <= 57) { // 48 == '0', 57 == '9'
          res *= 10;
          res += c - 48; // 48 == '0'
          c = this.read();
          if (isSpaceChar(c)) {
            return res * sgn;
          }
        }
  
        throw new InputMismatchException();
      }
  
      private static boolean isSpaceChar(final int c) {
        return c == 32 || c == 10 || c == 13 || c == 9
            || c == -1; // 32 == ' ', 10 == '\n', 13 == '\r', 9 == '\t'
      }
  
    }
  }
  
  