why would using "sftp" require disabling "vsftpd"?

[Marko Vojinovic]

On Fri, 07 Feb 2014 08:30:26 +0100
poma <pomidorabelisima at gmail.com> wrote:

> On 07.02.2014 02:04, Marko Vojinovic wrote:
> > On Fri, 07 Feb 2014 01:14:05 +0100
> > poma <pomidorabelisima at gmail.com> wrote:
> >>
> >> Secure File Transfer Protocol
> >> /etc/ssh/sshd_config
> >> Subsystem	sftp	/usr/libexec/openssh/sftp-server
> >>
> >> man 5 sshd_config
> >> man 8 sftp-server
> >> man 1 sftp
> >>
> >> 5+8+1=13!
> > 
> > Sorry, I failed to understand what you meant with this last bit
> > about sum to 13. Care to elaborate, please?
> 
> :)
> Thanks for asking!
> Actually with that phrase I stress somewhat of a misnomer for the
> program - "sftp".
> Some kind of comparison would be, if something like a web browser gets
> the name as "http".

Maybe I'm just dense today...

I understood your answer to the OP regarding the difference between
protocols, clients and stuff. What I didn't understand was the
connection of all that to the statement

> >> 5+8+1=13!

I mean, given that 5+8+1=14, am I missing some non-obvious humor here?
I really don't get it...

Best, :-)
Marko