def bsearch(low: int, high: int, pred) -> int:
    assert pred(low)
    lo = low
    hi = high
    res = low
    while lo <= hi:
        m = (lo + hi) // 2
        if pred(m):
            res = max(res, m)
            lo = m + 1
        else:
            hi = m - 1

    return res


def solve():
    def can(x: int) -> bool:
        a = N - 4 * x
        m = M + 4 * (a // 2)
        return a >= 0 and m >= 2 * x

    N, M = map(int, input().split())

    res = bsearch(0, 10**9, can)
    return res * 3


T = int(input())
for _ in range(T):
    ans = solve()
    print(ans)