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 the first two cases of topiramate - induced nephrolithiasis in the urologic literature .
### Output Text:
We report the first two cases of <span class="chemical">topiramate</span> - induced nephrolithiasis in the urologic literature . 