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: The effects of the adjunctive bupropion on male sexual dysfunction induced by a selective serotonin reuptake inhibitor : a double - blind placebo - controlled and randomized study .
### Output Text:
The effects of the adjunctive <span class="chemical">bupropion</span> on male sexual dysfunction induced by a <span class="chemical">selective serotonin reuptake inhibitor</span> : a double - blind placebo - controlled and randomized study . 