import heapq 
from heapq import heappop,heappush,heapify
from sys import stdin, setrecursionlimit
input = stdin.readline
readline = stdin.readline

from collections import deque
d=deque()

T=int(input())
for i in range(T):
  N,M=map(int,input().split())
  ng,ok=0,10**9
  while ok-ng>1:
    mid=(ok+ng)//2 
    f=1
    t=8*mid 
    if 4*mid<N:
      f=0 
    p=t-N 
    if p<M:
      f=0 
    if f==0:
      ng=mid 
    else:
      ok=mid 
  print(ok)
    








#A=list(map(int, input().split()))