Mort is the owner of an apartment building containing ten identical apartments. Mort resides in one apartment and rents out the remaining units. For 2018, the following information is available:

Gross rents

$21,600

Utilities for total building

2,500

Maintenance and repairs (rental apartments only)

1,050

Advertising for vacant apartments

300

Depreciation of building (all ten units)

4,000

What amount should Mort report as net rental income for 2018?