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: A patient with cryptogenic cirrhosis and disseminated sporotrichosis developed acute renal failure immediately following the administration of amphotericin B on four separate occasions .
### Output Text:
A patient with cryptogenic cirrhosis and disseminated sporotrichosis developed acute renal failure immediately following the administration of <span class="chemical">amphotericin B</span> on four separate occasions . 