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: Her medical history included coronary artery disease with previous myocardial infarctions , hypertension , and diabetes mellitus .
### Output Text:
Her medical history included coronary artery disease with previous myocardial infarctions , hypertension , and diabetes mellitus . 