import sys
# input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

"""

x - 2t
y + 4t
min((x - 2t) / 4, (y + 4t) / 2)

"""

def f(n, m, t):
    t = min(t, n // 2)
    # print(t)
    if 0 <= t and t * 2 <= n:
        return min((n - 2 * t) // 4,(m + 4 * t) // 2 )
    else:
        return -10 ** 18

for _ in range(ni()):
    n, m = na()
    # (x - 2t) = 2(y + 4t) 
    # x - 2y = 10t
    t = max((n - m * 2) // 10, 0)
    ans = - 10 ** 18
    ans = max(ans, f(n, m, t))
    ans = max(ans, f(n, m, t + 1))
    print(ans * 3)