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: CONCLUSIONS : In this study population , combination therapies with VAL / HCTZ were associated with significantly greater BP reductions compared with either monotherapy , were well tolerated , and were associated with less hypokalemia than HCTZ alone .
### Output Text:
CONCLUSIONS : In this study population , combination therapies with <span class="chemical">VAL</span> / <span class="chemical">HCTZ</span> were associated with significantly greater BP reductions compared with either monotherapy , were well tolerated , and were associated with less hypokalemia than <span class="chemical">HCTZ</span> alone . 