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: Concomitant IS consisted of mycophenolate mofetil + / - steroids .
### Output Text:
Concomitant IS consisted of <span class="chemical">mycophenolate mofetil</span> + / - <span class="chemical">steroids</span> . 