T = int(input())   



for _ in range(T):
    N, M = map(int, input().split())

    if  N == 0 and M == 0:
        Z = 0
    elif N == 0:
        Z = 0
    elif N > 0 and M >= 0:
        S1 = N // 4 
        S2 = M // 2
        if S1 == S2:
            Z = S1 * 3
        elif S1 < S2:
            Z = S1 * 3
        else:
            Z = S2 * 3 + (((S1 - S2) * 4 )//10 * 6)
    print(Z)