Q=int(input())
for _ in range(Q):
  N,M=map(int,input().split())
  if N%2==1:
    N-=1
  if M%2==1:
    M-=1
  if N<2*M:
    print(3*(N//4))
    continue
  result=3*(M//2)
  N-=4*(M//2)
  result+=6*(N//10)
  if N%10>=6:
    result+=3
  print(result)