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: Disulfiram - like syndrome after hydrogen cyanamide professional skin exposure : two case reports in France .
### Output Text:
<span class="chemical">Disulfiram</span> - like syndrome after <span class="chemical">hydrogen cyanamide</span> professional skin exposure : two case reports in France . 