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: //package com.company;
  
  import java.io.*;
  import java.math.BigInteger;
  import java.util.*;
  
  public class Main {
  
      static boolean[] primecheck = new boolean[1000002];
  
      public static void main(String[] args) throws IOException {
          OutputStream outputStream = System.out;
          FastReader in = new FastReader();
          PrintWriter out = new PrintWriter(outputStream);
          PROBLEM solver = new PROBLEM();
          int t = 1;
          t = in.nextInt();
          for (int i = 0; i < t; i++) {
              solver.solve(in, out);
          }
          out.close();
      }
  
      static class PROBLEM {
  
          public void solve(FastReader in, PrintWriter out) {
  
              long x = in.nextLong(), y = in.nextLong();
              long n = 0;
  
              if(x>y) n = x+y;
              else{
                  long r = ((y-x)/2) % x;
                  n = y - r;
              }
  
              //out.println(n%x == y%n);
  
              out.println(n);
  //            int n = in.nextInt();
  //            int[] a = in.readArray(n);
  //
  //            int ans = -1, cnt = 1, sam = 0;
  //            for (int i = 1; i < n; i++) {
  //                if(a[i] > a[i-1]){
  //                    cnt++;
  //                }else if(a[i] == a[i-1]){
  //                    sam++;
  //                    cnt++;
  //                }else{
  //                    if(ans == -1) ans = 0;
  //                    ans^=(cnt-sam);
  //                    if(ans == 0) break;
  //                    //out.println("cnt = " + cnt + " ans = " + ans );
  //                    cnt = 1;
  //                }
  //            }
  //            //out.println("cnt = " + cnt);
  //
  //            if(ans!=0) ans^=cnt;
  //
  //            //out.println(ans);
  
              //out.println((ans == 0) ? "YES" : "NO");
  
  
  
          }
      }
  
      static HashMap<Integer, Integer> initializeMap(int n){
          HashMap<Integer,Integer> hm = new HashMap<>();
          for (int i = 0; i <= n; i++) {
              hm.put(i, 0);
          }
          return hm;
      }
  
      static boolean isRegular(char[] c){
  
          Stack<Character> s = new Stack<>();
          for (char value : c) {
              if (s.isEmpty() && value == ')') return false;
  
              if (value == '(') s.push(value);
              else s.pop();
          }
  
          return s.isEmpty();
      }
  
      static ArrayList<ArrayList<Integer>> createAdj(int n, int e){
  
          FastReader in = new FastReader();
          ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
  
          for (int i = 0; i < n + 1; i++) {
              adj.add(new ArrayList<>());
          }
  
          for (int i = 0; i < e; i++) {
  
              int a = in.nextInt(), b = in.nextInt();
              System.out.println(a);
  
              adj.get(a).add(b);
              adj.get(b).add(a);
          }
  
  
          return adj;
      }
  
      static int binarySearch(int[] a, int l, int r, int x){
          if(r>=l){
              int mid = l + (r-l)/2;
  
              if(a[mid] == x) return mid;
  
              if(a[mid] > x) return binarySearch(a, l, mid-1, x);
              else return binarySearch(a,mid+1, r, x);
          }
          return -1;
      }
  
      static boolean isPalindromeI(int n){
  
          int d = 0;
          int y = n;
          while(y>0){
              d++;
              y/=10;
          }
  
          int[] a = new int[d];
          for (int i = 0; i < d; i++) {
              a[i] = n%10;
              n/=10;
          }
  
          System.out.println(Arrays.toString(a));
          for (int i = 0; i < d / 2; i++) {
              if(a[i] != a[d-i-1]) return false;
          }
          return true;
      }
  
      static long gcd(long a, long b) {
          if (b == 0) return a;
          return gcd(b, a % b);
      }
  
      static long lcm(long a, long b)
      {
          return (a / gcd(a, b)) * b;
      }
  
      static boolean isSquare(double a) {
          boolean isSq = false;
          double b = Math.sqrt(a);
          double c = Math.sqrt(a) - Math.floor(b);
  
          if (c == 0) isSq = true;
  
          return isSq;
      }
  
      static int exponentMod(int A, int B, int C) {
  
          // Base cases
          if (A == 0)
              return 0;
          if (B == 0)
              return 1;
  
          // If B is even
          long y;
          if (B % 2 == 0) {
              y = exponentMod(A, B / 2, C);
              y = (y * y) % C;
          }
  
          // If B is odd
          else {
              y = A % C;
              y = (y * exponentMod(A, B - 1, C) % C) % C;
          }
  
          return (int) ((y + C) % C);
      }
  
  
      static class Pair implements Comparable<Pair>{
  
          int x, y;
  
          Pair(int x, int y){
              this.x = x;
              this.y = y;
          }
  
          public int compareTo(Pair o){
              int ans = Integer.compare(y, o.y);
              //if(o.y == y) ans = Integer.compare(x, o.x);
  
              return ans;
          }
      }
  
      static class Tuple implements Comparable<Tuple>{
  
          int x, y, id;
  
          Tuple(int x, int y, int id){
              this.x = x;
              this.y = y;
              this.id = id;
          }
  
          public int compareTo(Tuple o){
              int ans = Integer.compare(x, o.x);
              if(o.x == x) ans = Integer.compare(y, o.y);
  
              return ans;
          }
      }
  
  //    public static class Pair<U extends Comparable<U>, V extends Comparable<V>> implements Comparable<Pair<U, V>> {
  //        public U x;
  //        public V y;
  //
  //        public Pair(U x, V y) {
  //            this.x = x;
  //            this.y = y;
  //        }
  //
  //        public int hashCode() {
  //            return (x == null ? 0 : x.hashCode() * 31) + (y == null ? 0 : y.hashCode());
  //        }
  //
  //        public boolean equals(Object o) {
  //            if (this == o)
  //                return true;
  //            if (o == null || getClass() != o.getClass())
  //                return false;
  //            Pair<U, V> p = (Pair<U, V>) o;
  //            return (x == null ? p.x == null : x.equals(p.x)) && (y == null ? p.y == null : y.equals(p.y));
  //        }
  //
  //        public int compareTo(Pair<U, V> b) {
  //            int cmpU = x.compareTo(b.x);
  //            return cmpU != 0 ? cmpU : y.compareTo(b.y);
  //        }
  //
  //        public String toString() {
  //            return String.format("(%s, %s)", x.toString(), y.toString());
  //        }
  //
  //    }
  
      static class FastReader {
          BufferedReader br;
          StringTokenizer st;
  
          public FastReader() {
              br = new BufferedReader(new InputStreamReader(System.in));
          }
  
          String next() {
              while (st == null || !st.hasMoreElements()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              }
              return st.nextToken();
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
  
          long nextLong() {
              return Long.parseLong(next());
          }
  
          double nextDouble() {
              return Double.parseDouble(next());
          }
  
          char nextChar() {
              return next().charAt(0);
          }
  
          boolean nextBoolean() {
              return !(nextInt() == 0);
          }
          // boolean nextBoolean(){return Boolean.parseBoolean(next());}
  
          String nextLine() {
              String str = "";
              try {
                  str = br.readLine();
              } catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
  
          public int[] readArray(int size) {
              int[] array = new int[size];
              for (int i = 0; i < size; i++) array[i] = nextInt();
              return array;
          }
  
      }
  
      private static int[] mergeSort(int[] array) {
  
          //array.length replaced with ctr
          int ctr = array.length;
          if (ctr <= 1) {
              return array;
          }
  
          int midpoint = ctr / 2;
  
          int[] left = new int[midpoint];
          int[] right;
  
          if (ctr % 2 == 0) {
              right = new int[midpoint];
          } else {
              right = new int[midpoint + 1];
          }
  
          for (int i = 0; i < left.length; i++) {
              left[i] = array[i];
          }
  
          for (int i = 0; i < right.length; i++) {
              right[i] = array[i + midpoint];
          }
  
          int[] result = new int[array.length];
  
          left = mergeSort(left);
          right = mergeSort(right);
  
          result = merge(left, right);
  
          return result;
      }
  
      private static int[] merge(int[] left, int[] right) {
  
          int[] result = new int[left.length + right.length];
          int leftPointer = 0, rightPointer = 0, resultPointer = 0;
  
          while (leftPointer < left.length || rightPointer < right.length) {
  
              if (leftPointer < left.length && rightPointer < right.length) {
  
                  if (left[leftPointer] < right[rightPointer]) {
                      result[resultPointer++] = left[leftPointer++];
                  } else {
                      result[resultPointer++] = right[rightPointer++];
                  }
              } else if (leftPointer < left.length) {
                  result[resultPointer++] = left[leftPointer++];
              } else {
                  result[resultPointer++] = right[rightPointer++];
              }
          }
          return result;
      }
  
      public static void Sieve(int n) {
  
          Arrays.fill(primecheck, true);
          primecheck[0] = false;
          primecheck[1] = false;
  
          for (int i = 2; i * i < n + 1; i++) {
              if (primecheck[i]) {
                  for (int j = i * 2; j < n + 1; j += i) {
                      primecheck[j] = false;
                  }
              }
          }
      }
  }
  
  
  