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: Importantly , GNC92H2 prevented death even post - cocaine injection .
### Output Text:
Importantly , <span class="chemical">GNC92H2</span> prevented death even post - <span class="chemical">cocaine</span> injection . 