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.
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  import os
  import sys
  from io import BytesIO, IOBase
  #-----------------------IMPORTANT  FUNCTIONS ---------------------------------#
  from math import cos, pi, ceil, pi, tan, floor, gcd, sqrt, log2, factorial, log10
  from collections import Counter
  from copy import deepcopy
  from string import ascii_lowercase, ascii_uppercase
  from statistics import mean, median, mode
  from bisect import *
  
  alpha = ascii_lowercase
  beta = ascii_uppercase
  
  
  #-----------------------NEXT POWER OF 2---------------------------------------#
  def nextPowerOf2(n):
      p = 1
      if (n and not (n & (n - 1))):
          return n
      while (p < n):
          p <<= 1
      return p
  #-----------------------COMPOSITE  CHECK---------------------------------------#
  def isComposite(n):
      if (n <= 1):
          return False
      if (n <= 3):
          return False
      if (n % 2 == 0 or n % 3 == 0):
          return True
      i = 5
      while(i * i <= n):
          if (n % i == 0 or n % (i + 2) == 0):
              return True
          i = i + 6
      return False
  
  
  #-----------------------GET DIVISORS 1 TO <=N   ------------------------------#
  def get_Divisors(n):
      arr = []
      i = 1
      while i <= sqrt(n):
          if (n % i == 0):
              if (n / i == i):
                  arr.append(i)
              else:
                  arr.append(i)
                  arr.append(n // i)
          i = i + 1
  
      return arr
  
  
  #----------------------CHECK    PRIMES-----------------------------------#
  def isprime(n):
      if n == 1:
          return 0
      i = 2
      while (i * i <= n):
          if (n % i == 0):
              return 0
          i += 1
      return 1
  
  
  #-----------------------PRE COMPUTED  PRIMES-----------------------------------#
  def Sieve(n):
      prime = [True for i in range(n + 1)]
      prime[0] = False
      prime[1] = False
      p = 2
      while (p * p <= n):
          if (prime[p] == True):
              for i in range(p * p, n + 1, p):
                  prime[i] = False
          p += 1
      return prime
  
  
  #-----------------------LARGER VALUE OF  X,Y,10**9+7 --------------------------#
  def power(x, y, p):
      res = 1
      x = x % p
      if (x == 0):
          return 0
      while (y > 0):
          if ((y & 1) == 1):
              res = (res * x) % p
          y = y >> 1
          x = (x * x) % p
      return res
  
  
  #-----------------------       CREATE MATRIX         --------------------------#
  def create_matrix(n, m):
      mat = [[] for i in range(n)]
      for i in range(n):
          for j in range(m):
              mat[i].append(0)
      return mat
  
  
  #By Default Counter stores the value in decending orderCounter({4: 2, 8: 2, 2: 1, 9: 1}
  #s=sorted(s.items(),key=lambda k:(k[0],k[1])) ---> [(2, 1), (4, 2), (8, 2), (9, 1)]
  #sort 2nd value  from bada se chhota  then(4,2)(8,2)->>(8,2)(4,2) s=sorted(s.items(),key=lambda k:(-k[1],-k[0]))  [(8, 2), (4, 2), (9, 1), (2, 1)]
  #for list pair in a list    s.sort(key=lambda k:(-k[1],-k[0])) [[3, 4], [8, 2], [4, 2]]
  # from functools import cmp_to_key
  #how to use compare ----ss = sorted(s, key=cmp_to_key(compare))
  #-----------------------*****CODE STARTS  HERE*****--------------------------#
  
  # from queue import Queue
  # from random import *
  def main():
      for ttt in range(int(input())):
          x,y=map(int,input().split())
          if x>y:
              print(x+y)
          elif x==y:
              print(x)
          else:
              m=y//x 
              mm=m*x 
              print((mm+y)//2)
              
          
              
          
  # Region Fast_______io
  BUFSIZE = 8192
  class FastIO(IOBase):
      newlines = 0
  
      def __init__(self, file):
          self._fd = file.fileno()
          self.buffer = BytesIO()
          self.writable = "x" in file.mode or "r" not in file.mode
          self.write = self.buffer.write if self.writable else None
  
      def read(self):
          while True:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              if not b:
                  break
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines = 0
          return self.buffer.read()
  
      def readline(self):
          while self.newlines == 0:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              self.newlines = b.count(b"\n") + (not b)
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines -= 1
          return self.buffer.readline()
  
      def flush(self):
          if self.writable:
              os.write(self._fd, self.buffer.getvalue())
              self.buffer.truncate(0), self.buffer.seek(0)
  
  
  class IOWrapper(IOBase):
      def __init__(self, file):
          self.buffer = FastIO(file)
          self.flush = self.buffer.flush
          self.writable = self.buffer.writable
          self.write = lambda s: self.buffer.write(s.encode("ascii"))
          self.read = lambda: self.buffer.read().decode("ascii")
          self.readline = lambda: self.buffer.readline().decode("ascii")
  
  
  #sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
  input = lambda: sys.stdin.readline().rstrip("\r\n")
  if __name__ == "__main__":
      main()