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 Australia , the pediatric usage of aspirin has been extremely low for the past 25 years ( less than 1 % of total dosage units sold ) , with paracetamol ( acetaminophen ) dominating the pediatric analgesic and antipyretic market .
### Output Text:
In Australia , the pediatric usage of <span class="chemical">aspirin</span> has been extremely low for the past 25 years ( less than 1 % of total dosage units sold ) , with <span class="chemical">paracetamol</span> ( <span class="chemical">acetaminophen</span> ) dominating the pediatric analgesic and antipyretic market . 