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: /**
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   * https://tinyurl.com/zdxe2y4z
   * I do screencasts, solutions, and other fun stuff in the future
   */
  
  import java.util.*;
  import java.io.*;
  import static java.lang.Math.min;
  import static java.lang.Math.abs;
  import static java.lang.Math.max;
  public class EdA {
  	static long[] mods = {1000000007, 998244353, 1000000009};
  	static long mod = mods[0];
  	public static MyScanner sc;
      public static PrintWriter out;
  	public static void main(String[] largewang) throws Exception{
  		// TODO Auto-generated method stub
   		sc = new MyScanner();
   		out = new PrintWriter(System.out);
   		int t = sc.nextInt();
   		while (t-->0) {
   			int x = sc.nextInt();
   			int y = sc.nextInt();
   			if (x > y){
   				out.println(x+y);
   			} else if (x == y){
   				out.println(x);
   			} else if ((long)x * 3L > y){
   				out.println((x+y)/2);
   			}else{
   				int val = y%x;
   				out.println(y - val/2);
   			}
   			
   		}
   		out.close();
   		
   	}
  	public static long gcd(long a, long b){ 
  	      if (b == 0) 
  	        return a; 
  	      return gcd(b, a % b);  
  	    }
  	public static void sort(int[] array){
  		ArrayList<Integer> copy = new ArrayList<>();
  		for (int i : array)
  			copy.add(i);
  		Collections.sort(copy);
  		for(int i = 0;i<array.length;i++)
  			array[i] = copy.get(i);
  	}
  	static String[] readArrayString(int n){
  		String[] array = new String[n];
  		for(int j =0 ;j<n;j++)
  			array[j] = sc.next();
  		return array;
  	}
  	static int[] readArrayInt(int n){
      	int[] array = new int[n];
      	for(int j = 0;j<n;j++)
      		array[j] = sc.nextInt();
      	return array;
      }
  	static int[] readArrayInt1(int n){
  		int[] array = new int[n+1];
  		for(int j = 1;j<=n;j++){
  			array[j] = sc.nextInt();
  		}
  		return array;
  	}
  	static long[] readArrayLong(int n){
  		long[] array = new long[n];
  		for(int j =0 ;j<n;j++)
  			array[j] = sc.nextLong();
  		return array;
  	}
  	static double[] readArrayDouble(int n){
  		double[] array = new double[n];
  		for(int j =0 ;j<n;j++)
  			array[j] = sc.nextDouble();
  		return array;
  	}
  	static int minIndex(int[] array){
  		int minValue = Integer.MAX_VALUE;
  		int minIndex = -1;
  		for(int j = 0;j<array.length;j++){
  			if (array[j] < minValue){
  				minValue = array[j];
  				minIndex = j;
  			}
  		}
  		return minIndex;
  	}
  	static int minIndex(long[] array){
  		long minValue = Long.MAX_VALUE;
  		int minIndex = -1;
  		for(int j = 0;j<array.length;j++){
  			if (array[j] < minValue){
  				minValue = array[j];
  				minIndex = j;
  			}
  		}
  		return minIndex;
  	}
  	static int minIndex(double[] array){
  		double minValue = Double.MAX_VALUE;
  		int minIndex = -1;
  		for(int j = 0;j<array.length;j++){
  			if (array[j] < minValue){
  				minValue = array[j];
  				minIndex = j;
  			}
  		}
  		return minIndex;
  	}
  	static long power(long x, long y){
  		if (y == 0)
  			return 1;
  		if (y%2 == 1)
  			return (x*power(x, y-1))%mod;
  		return power((x*x)%mod, y/2)%mod;
  	}
  	static void verdict(boolean a){
          out.println(a ? "YES" : "NO");
      }
      public static class MyScanner {
          BufferedReader br;
          StringTokenizer st;
          public MyScanner() {
              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());
          }
          String nextLine() {
              String str = "";
              try{
                  str = br.readLine();
              } 
              catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
          
      }	
  }
  
  //StringJoiner sj = new StringJoiner(" "); 
  //sj.add(strings)
  //sj.toString() gives string of those stuff w spaces or whatever that sequence is