T = int(input())
for t in range(T):

    N, M = map(int, input().split())
        
    if N % 2 == 1:
        N -= 1
    if M % 2 == 1: 
        M -= 1

    if N < 2 * M:
        print(3 * (N // 4))
    else:
        ans = 3 * (M // 2)
        N -= 2 * M
        M = 0
        ans += 6 * (N // 10)
        N %= 10
        if 6 <= N:
            ans += 3

        print(ans)