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 contrast with other beta blockers , flestolol - induced effects reverse rapidly ( within 30 minutes ) following discontinuation because of its short half - life .
### Output Text:
In contrast with other beta blockers , <span class="chemical">flestolol</span> - induced effects reverse rapidly ( within 30 minutes ) following discontinuation because of its short half - life . 