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: Cocaine - induced mood disorder : prevalence rates and psychiatric symptoms in an outpatient cocaine - dependent sample .
### Output Text:
<span class="chemical">Cocaine</span> - induced mood disorder : prevalence rates and psychiatric symptoms in an outpatient <span class="chemical">cocaine</span> - dependent sample . 