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: Although initially thought to be free of extrapyramidal side effects , sulpiride - induced tardive dyskinesia and parkinsonism have been reported occasionally .
### Output Text:
Although initially thought to be free of extrapyramidal side effects , <span class="chemical">sulpiride</span> - induced tardive dyskinesia and parkinsonism have been reported occasionally . 