import math
T = int(input())
for i in range(T):
  n, m = map(int, input().split())
  ok = 10 ** 18
  ng = 0
  while ng + 1 < ok:
    mid = (ok + ng) // 2
    if 4 * mid >= n and mid * 8 >= m + n:
      ok = mid
    else:
      ng = mid
  print(ok)