def solve():
    def f(n, m):
        if n <= m:
            return n // 4
        elif m > 0:
            cnt = m // 2
            nn = n - 4 * cnt
            return cnt + f(nn, 0)
        elif m == 0:
            d, m = divmod(n, 10)
            cnt = 2 * d
            return cnt + (1 if m >= 6 else 0)
        else:
            assert False

    N, M = map(int, input().split())
    return 3 * f(N, M)


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