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: Amiodarone and atazanavir are recognized CYP3A4 inhibitors .
### Output Text:
<span class="chemical">Amiodarone</span> and <span class="chemical">atazanavir</span> are recognized CYP3A4 inhibitors . 