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: Treatment - related adverse events ( AEs ) occurred in 44 % and 52 % , 57 % , and 41 % of the asenapine at 5 and 10 mg BID , haloperidol , and placebo groups , respectively .
### Output Text:
Treatment - related adverse events ( AEs ) occurred in 44 % and 52 % , 57 % , and 41 % of the <span class="chemical">asenapine</span> at 5 and 10 mg BID , <span class="chemical">haloperidol</span> , and placebo groups , respectively . 