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: From the analysis of these cases , two distinct forms of carbamazepine - associated cardiac dysfunction emerged .
### Output Text:
From the analysis of these cases , two distinct forms of <span class="chemical">carbamazepine</span> - associated cardiac dysfunction emerged . 