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: The incidence of hypokalemia was lower with VAL / HCTZ combinations ( 1 . 8 % - 6 . 1 % ) than with HCTZ monotherapies ( 7 . 1 % - 13 . 3 % ) .
### Output Text:
The incidence of hypokalemia was lower with <span class="chemical">VAL</span> / <span class="chemical">HCTZ</span> combinations ( 1 . 8 % - 6 . 1 % ) than with <span class="chemical">HCTZ</span> monotherapies ( 7 . 1 % - 13 . 3 % ) . 