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: Treatment of risperidone - induced hyperprolactinemia with a dopamine agonist in children .
### Output Text:
Treatment of <span class="chemical">risperidone</span> - induced hyperprolactinemia with a <span class="chemical">dopamine</span> agonist in children . 