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: Methyldopa - induced hemolytic anemia in a 15 year old presenting as near - syncope .
### Output Text:
<span class="chemical">Methyldopa</span> - induced hemolytic anemia in a 15 year old presenting as near - syncope . 