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: On the contrary , the SM - 5887 treatment did not progress the grade of cardiomyopathy .
### Output Text:
On the contrary , the <span class="chemical">SM - 5887</span> treatment did not progress the grade of cardiomyopathy . 