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: DRC for HR ( p less than 0 . 001 ) , K ( p less than 0 . 001 ) , and Glu ( p less than 0 . 005 ) were attenuated after treatment with HDS compared with PI .
### Output Text:
DRC for HR ( p less than 0 . 001 ) , <span class="chemical">K</span> ( p less than 0 . 001 ) , and <span class="chemical">Glu</span> ( p less than 0 . 005 ) were attenuated after treatment with HDS compared with PI . 