description: YouKn0wWho has two even integers x and y. Help him to find an integer n such that 1 ≤ n ≤ 2 ⋅ 10^{18} and n mod x = y mod n. Here, a mod b denotes the remainder of a after division by b. If there are multiple such integers, output any. It can be shown that such an integer always exists under the given constraints.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10^5) — the number of test cases.
  
  The first and only line of each test case contains two integers x and y (2 ≤ x, y ≤ 10^9, both are even).
  
  Output
  
  For each test case, print a single integer n (1 ≤ n ≤ 2 ⋅ 10^{18}) that satisfies the condition mentioned in the statement. If there are multiple such integers, output any. It can be shown that such an integer always exists under the given constraints.
  
  Example
  
  Input
  
  
  4
  4 8
  4 2
  420 420
  69420 42068
  
  
  Output
  
  
  4
  10
  420
  9969128
  
  Note
  
  In the first test case, 4 mod 4 = 8 mod 4 = 0.
  
  In the second test case, 10 mod 4 = 2 mod 10 = 2.
  
  In the third test case, 420 mod 420 = 420 mod 420 = 0.
solution: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.PrintWriter;
  import java.io.BufferedWriter;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.StringTokenizer;
  import java.io.Writer;
  import java.io.OutputStreamWriter;
  import java.io.BufferedReader;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          OutputWriter out = new OutputWriter(outputStream);
          DModerateModularMode solver = new DModerateModularMode();
          int testCount = Integer.parseInt(in.next());
          for (int i = 1; i <= testCount; i++)
              solver.solve(i, in, out);
          out.close();
      }
  
      static class DModerateModularMode {
          public void solve(int testNumber, InputReader in, OutputWriter out) {
              long x = in.nextLong(), y = in.nextLong();
              long ans = 0;
              if (y > x) {
                  if (y % x == 0) {
                      ans = y;
                  } else {
                      long rem = y % x;
                      ans = (y / x) * x + rem / 2;
                  }
              } else if (y == x) {
                  ans = y;
              } else {
                  ans = x + y;
              }
              out.println(ans);
          }
  
      }
  
      static class OutputWriter {
          private final PrintWriter writer;
  
          public OutputWriter(OutputStream outputStream) {
              writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
          }
  
          public OutputWriter(Writer writer) {
              this.writer = new PrintWriter(writer);
          }
  
          public void close() {
              writer.close();
          }
  
          public void println(long i) {
              writer.println(i);
          }
  
      }
  
      static class InputReader {
          BufferedReader reader;
          StringTokenizer tokenizer;
  
          public InputReader(InputStream stream) {
              reader = new BufferedReader(new InputStreamReader(stream), 32768);
              tokenizer = null;
          }
  
          public String next() {
              while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                  try {
                      tokenizer = new StringTokenizer(reader.readLine());
                  } catch (IOException e) {
                      throw new RuntimeException(e);
                  }
              }
              return tokenizer.nextToken();
          }
  
          public long nextLong() {
              return Long.parseLong(next());
          }
  
      }
  }
  
  