program main
    integer t, n, m, ans, usen, temp
    
    read *, t
    do i = 0, t
        read *, n, m
        usen = 0
        ans = 3*min(n/4,m/2)
        do
            usen = usen + 2
            temp = 3*min((n-usen)/4,(m+2*usen)/2)
            if (ans > temp) then
                exit
            else
                ans = temp
            end if
        end do
        write (6,fmt='(I0)') ans
    end do
end program main