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: Post hoc analyses indicated that efficacy was similar with asenapine and haloperidol ; greater contrasts were seen in AEs , especially extrapyramidal symptoms .
### Output Text:
Post hoc analyses indicated that efficacy was similar with <span class="chemical">asenapine</span> and <span class="chemical">haloperidol</span> ; greater contrasts were seen in AEs , especially extrapyramidal symptoms . 