ML350 Rack Type with 30 Disks - clarrification

Hi HP Guru,

We have an ML350 Gen9 (Rack Chassis) with 1x Smart Array 840/4G.

How many SAS Expander do we need to support 30 Disks ?

Can a single SAS Expander support all 30 Disks?

Hoping for your quick response.

Thank you