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: Two acetaminophen - induced ALF patients reattempted suicide post - LT ( one died 8 years post - LT ) .
### Output Text:
Two <span class="chemical">acetaminophen</span> - induced ALF patients reattempted suicide post - LT ( one died 8 years post - LT ) . 