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 present study examines the safety and tolerability of high - compared with low - dose lisinopril in CHF .
### Output Text:
The present study examines the safety and tolerability of high - compared with low - dose <span class="chemical">lisinopril</span> in CHF . 