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: Twenty ( 56 % ) acetaminophen - induced ALF patients had a formal psychiatric diagnosis before LT ( non - acetaminophen - induced ALF = 0 / 35 , CLD = 2 / 34 ; P < 0 . 01 for all ) and nine ( 25 % ) had a previous suicide attempt .
### Output Text:
Twenty ( 56 % ) <span class="chemical">acetaminophen</span> - induced ALF patients had a formal psychiatric diagnosis before LT ( non - <span class="chemical">acetaminophen</span> - induced ALF = 0 / 35 , CLD = 2 / 34 ; P < 0 . 01 for all ) and nine ( 25 % ) had a previous suicide attempt . 