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.*;
  import java.util.*;
  import java.math.*;
  import java.lang.*;
  
  public class Gcd_Queries  implements Runnable {
      static class InputReader {
          private InputStream stream;
          private byte[] buf = new byte[1024];
          private int curChar;
          private int numChars;
          private SpaceCharFilter filter;
          private BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  
          public InputReader(InputStream stream) {
              this.stream = stream;
          }
  
          public int read() {
              if (numChars == -1)
                  throw new InputMismatchException();
  
              if (curChar >= numChars) {
                  curChar = 0;
                  try {
                      numChars = stream.read(buf);
                  } catch (IOException e) {
                      throw new InputMismatchException();
                  }
  
                  if (numChars <= 0)
                      return -1;
              }
              return buf[curChar++];
          }
  
          public String nextLine() {
              String str = "";
              try {
                  str = br.readLine();
              } catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
  
          public int nextInt() {
              int c = read();
  
              while (isSpaceChar(c))
                  c = read();
  
              int sgn = 1;
  
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
  
              int res = 0;
              do {
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              } while (!isSpaceChar(c));
  
              return res * sgn;
          }
  
          public long nextLong() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              long res = 0;
  
              do {
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              } while (!isSpaceChar(c));
              return res * sgn;
          }
  
          public double nextDouble() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              double res = 0;
              while (!isSpaceChar(c) && c != '.') {
                  if (c == 'e' || c == 'E')
                      return res * Math.pow(10, nextInt());
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              }
              if (c == '.') {
                  c = read();
                  double m = 1;
                  while (!isSpaceChar(c)) {
                      if (c == 'e' || c == 'E')
                          return res * Math.pow(10, nextInt());
                      if (c < '0' || c > '9')
                          throw new InputMismatchException();
                      m /= 10;
                      res += (c - '0') * m;
                      c = read();
                  }
              }
              return res * sgn;
          }
  
          public String readString() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              StringBuilder res = new StringBuilder();
              do {
                  res.appendCodePoint(c);
                  c = read();
              } while (!isSpaceChar(c));
  
              return res.toString();
          }
  
          public boolean isSpaceChar(int c) {
              if (filter != null)
                  return filter.isSpaceChar(c);
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
          public String next() {
              return readString();
          }
  
          public interface SpaceCharFilter {
              public boolean isSpaceChar(int ch);
          }
      }
  
      public static void main(String args[]) throws Exception {
          new Thread(null, new Gcd_Queries (), "Main", 1 << 27).start();
      }
  
      static class Pair {
          int f;
          int s;
          int p;
          PrintWriter w;
  
          // int t;
  
          Pair(int f, int s) {
              // Pair(int f,int s, PrintWriter w){
              this.f = f;
              this.s = s;
              // this.p = p;
              // this.w = w;
              // this.t = t;
  
          }
  
          public static Comparator<Pair> wc = new Comparator<Pair>() {
              public int compare(Pair e1,Pair e2){
  
                  // 1 for swap
                  if(Math.abs(e1.f)-Math.abs(e2.f)!=0){
                      // e1.w.println("**"+e1.f+" "+e2.f);
                      return (Math.abs(e1.f)-Math.abs(e2.f));
                  }
                  else{
                      // e1.w.println("##"+e1.f+" "+e2.f);
                      return (Math.abs(e1.s)-Math.abs(e2.s));
                  }
  
  
              }
          };
      }
  
      public Integer[] sort(Integer[] a) {
          Arrays.sort(a);
          return a;
      }
  
      public Long[] sort(Long[] a) {
          Arrays.sort(a);
          return a;
      }
  
      public static ArrayList<Integer> sieve(int N) {
          int i, j, flag;
  
          ArrayList<Integer> p = new ArrayList<Integer>();
  
          for (i = 1; i < N; i++) {
  
              if (i == 1 || i == 0)
                  continue;
  
              flag = 1;
  
              for (j = 2; j <= i / 2; ++j) {
                  if (i % j == 0) {
                      flag = 0;
                      break;
                  }
              }
              if (flag == 1) {
                  p.add(i);
              }
          }
          return p;
      }
  
      public static long gcd(long a, long b) {
          if (b == 0)
              return a;
          else
              return gcd(b, a % b);
      }
  
      public static int gcd(int a, int b) {
          if (b == 0)
              return a;
          else
              return gcd(b, a % b);
      }
  
      //// recursive dfs
      public static int dfs(int s, ArrayList<Integer>[] g, long[] dist, boolean[] v, PrintWriter w, int p) {
          v[s] = true;
          int ans = 1;
          // int n = dist.length - 1;
          int t = g[s].size();
          // int max = 1;
          for (int i = 0; i < t; i++) {
              int x = g[s].get(i);
              if (!v[x]) {
                  // dist[x] = dist[s] + 1;
                  ans = Math.min(ans, dfs(x, g, dist, v, w, s));
              } else if (x != p) {
                  // w.println("* " + s + " " + x + " " + p);
                  ans = 0;
              }
          }
          // max = Math.max(max,(n-p));
          return ans;
      }
  
      //// iterative BFS
      public static int bfs(int s, ArrayList<Integer>[] g, long[] dist, boolean[] b, PrintWriter w, int p) {
          b[s] = true;
          int siz = 1;
          // dist--;
          Queue<Integer> q = new LinkedList<>();
          q.add(s);
          while (q.size() != 0) {
              int i = q.poll();
              Iterator<Integer> it = g[i].listIterator();
              int z = 0;
              while (it.hasNext()) {
                  z = it.next();
                  if (!b[z]) {
                      b[z] = true;
                      // dist--;
                      dist[z] = dist[i] + 1;
                      // siz++;
                      q.add(z);
                  } else if (z != p) {
                      siz = 0;
                  }
              }
  
          }
          return siz;
      }
  
      public static int lower(int a[], int x) { // x is the target value or key
          int l = -1, r = a.length;
          while (l + 1 < r) {
              int m = (l + r) >>> 1;
              if (a[m] >= x)
                  r = m;
              else
                  l = m;
          }
          return r;
      }
  
      public static int upper(int a[], int x) {// x is the key or target value
          int l = -1, r = a.length;
          while (l + 1 < r) {
              int m = (l + r) >>> 1;
              if (a[m] <= x)
                  l = m;
              else
                  r = m;
          }
          return l + 1;
      }
  
      public static int lower(ArrayList<Integer> a, int x) { // x is the target value or key
          int l = -1, r = a.size();
          while (l + 1 < r) {
              int m = (l + r) >>> 1;
              if (a.get(m) >= x)
                  r = m;
              else
                  l = m;
          }
          return r;
      }
  
      public static int upper(ArrayList<Integer> a, int x) {// x is the key or target value
          int l = -1, r = a.size();
          while (l + 1 < r) {
              int m = (l + r) >>> 1;
              if (a.get(m) <= x)
                  l = m;
              else
                  r = m;
          }
          return l + 1;
      }
  
      public static long power(long x, long y, long m) {
          if (y == 0)
              return 1;
  
          long p = power(x, y / 2, m) % m;
          p = (p * p) % m;
  
          if (y % 2 == 0)
              return p;
          else
              return (x * p) % m;
      }
  
      public void yesOrNo(boolean f) {
          if (f) {
              w.println("YES");
          } else {
              w.println("NO");
          }
      }
          public boolean isPrime(int n)
          {
              if (n <= 1)
                  return false;
              if (n <= 3)
                  return true;
              if (n % 2 == 0 || n % 3 == 0)
                  return false;
              for (int i = 5; i * i <= n; i = i + 6)
                  if (n % i == 0 || n % (i + 2) == 0)
                      return false;
        
              return true;
          }
      
  
      // Arrays.sort(rooms, (room1, room2) -> room1[1] == room2[1] ? room1[0]-room2[0]
      // : room2[1]-room1[1]);
      // Arrays.sort(A, (a, b) -> Integer.compare(a[0] , b[0]));
      //////////////////////////////////////////////////////////////////////////////////////////////////////
      //////////////////////////////////////////////////////////////////////////////////////////////////////
      // code here
      int oo = (int) 1e9;
      int[] parent;
      int[] dist;
      int[][] val;
      boolean[][] vis;
      ArrayList<Integer>[] g;
      // int[] col;
      // HashMap<Long, Boolean>[] dp;
      //char[][] g;
      // boolean[][] v;
      Long[] a;
      // ArrayList<Integer[]> a;
      // int[][] ans;
      long[][] dp;
      long mod;
      int n;
      int m;
      int k;
      long[][] pre;
      // StringBuilder[] a;
      // StringBuilder[] b;
      // StringBuilder ans;
      int[][] col;
      int[][] row;
      PrintWriter w = new PrintWriter(System.out);
  
      public void run() {
  
          InputReader sc = new InputReader(System.in);
          int tt = sc.nextInt();
          while(tt-->0){
             int x = sc.nextInt();
             int y = sc.nextInt();
  
             if(x<=y){
                 w.println(y-y%x/2);
             }else{
                 w.println(x+y);
             }
            
          
          }
          w.flush();
          w.close();
  
      }
     
  }
  
  