def check(n, m, x):
    if m<x*2:
        dif = x*2-m
        cnt = (dif+3)//4
        n -= 2*cnt
        m += 4*cnt
    if n>=x*4 and m>=x*2:
        return True
    return False

import sys
input = sys.stdin.readline
T = int(input())
NM = [list(map(int, input().split())) for _ in range(T)]
INF = 10**9
for n, m in NM:
    l = 0
    r = INF
    while r-l>1:
        mid = (l+r)//2
        if check(n, m, mid):
            l = mid
        else:
            r = mid
    print(l*3)