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 sys
  testing = len(sys.argv) == 4 and sys.argv[3] == "myTest"
  interactive = False
  if testing:
      cmd = sys.stdout
      from time import time
      start_time = int(round(time() * 1000)) 
      readAll = open(sys.argv[1], 'r').read
      sys.stdout = open(sys.argv[2], 'w')
  else:
      readAll = sys.stdin.read
  
  # ############ ---- I/O Functions ---- ############
  
  class InputData:
      def __init__(self):
          self.lines = readAll().split('\n')
          self.n = len(self.lines)
          self.ii = -1
      def input(self):
          self.ii += 1
          assert self.ii < self.n
          return self.lines[self.ii]
  
  flush = sys.stdout.flush
  if interactive and not testing:
      input = sys.stdin.readline
  else:
      inputData = InputData()
      input = inputData.input
  
  def intin():
      return(int(input()))
  def intlin():
      return(list(map(int,input().split())))
  def chrin():
      return(list(input()))
  def strin():
      return input()
  def lout(l, sep="\n", toStr=True):
      print(sep.join(map(str, l) if toStr else l))
  def dout(*args, **kargs):
      if not testing: return
      if args: print(args[0] if len(args)==1 else args)
      if kargs: print([(k,v) for k,v in kargs.items()])
  def ask(q):
      sys.stdout.write(str(q)+'\n')
      flush()
      return intin()
      
  # ############ ---- I/O Functions ---- ############
  
  # from math import ceil
  # from collections import defaultdict as ddict, Counter
  # from heapq import *
  # from Queue import Queue
  
  def main():
      x,y = intlin()
      if x > y:
          return x+y
      if x == y:
          return x
      # x < y
      if y%x == 0:
          return x
      if y < 3*x:
          return (x+y)/2
      k = y/x-1
      return (k*x+y)/2
  
  
  anss = []
  for _ in xrange(intin()):
      anss.append(main())
      # anss.append("YES" if main() else "NO")
  lout(anss)
  
  if testing:
      sys.stdout = cmd
      print(int(round(time() * 1000))  - start_time)