import sys

from typing import List, Tuple

int1 = lambda x: int(x) - 1
input = lambda: sys.stdin.readline().rstrip('\n')
ii = lambda: int(input())
vi = lambda: list(map(int, input().split()))
vi1 = lambda: list(map(int1, input().split()))


def dbg(*args, **kwargs):
    print(*(repr(arg) for arg in args), *(f'{k}: {repr(v)}' for k, v in kwargs.items()),
          sep='; ', file=sys.stderr, flush=True)


def main():
    t = ii()
    for _ in range(t):
        n, m = vi()
        f = min(n // 4, m // 2)
        n -= 4 * f
        m -= 2 * f
        f2 = (n // 10) * 2
        n %= 10
        f3 = n // 6
        n %= 6
        print((f + f2 + f3) * 3)


def _start():
    if (ret := main()) is not None:
        print(*ret) if isinstance(ret, List) or isinstance(ret, Tuple) else print(ret)


if __name__ == '__main__':
    _start()