In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: We report a female patient with a diagnosis of a not otherwise specified psychotic disorder ( DSM - IV ) who developed hypomania shortly after the introduction of olanzapine treatment .
### Output Text:
We report a female patient with a diagnosis of a not otherwise specified psychotic disorder ( DSM - IV ) who developed hypomania shortly after the introduction of <span class="chemical">olanzapine</span> treatment . 