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: In addition , ease of application of CHP creams was less satisfactory than that of AgSD .
### Output Text:
In addition , ease of application of <span class="chemical">CHP</span> creams was less satisfactory than that of <span class="chemical">AgSD</span> . 