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: Amphotericin B concentrations in the kidney in NS - 718 - treated rats were higher than those in D - AmB - treated rats .
### Output Text:
<span class="chemical">Amphotericin B</span> concentrations in the kidney in NS - 718 - treated rats were higher than those in <span class="chemical">D - AmB</span> - treated rats . 