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: Rhabdomyolysis in association with simvastatin and dosage increment in clarithromycin .
### Output Text:
Rhabdomyolysis in association with <span class="chemical">simvastatin</span> and dosage increment in <span class="chemical">clarithromycin</span> . 