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: A 30 - year - old cocaine - dependent man who was a subject in a study evaluating the anticraving efficacy of the stimulant medication diethylpropion ( DEP ) became manic during his second week on the study drug .
### Output Text:
A 30 - year - old <span class="chemical">cocaine</span> - dependent man who was a subject in a study evaluating the anticraving efficacy of the stimulant medication <span class="chemical">diethylpropion</span> ( <span class="chemical">DEP</span> ) became manic during his second week on the study drug . 