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: In individuals with preexisting , high - grade coronary arterial narrowing , acute myocardial infarction may result from an increase in myocardial oxygen demand associated with cocaine - induced increase in rate - pressure product .
### Output Text:
In individuals with preexisting , high - grade coronary arterial narrowing , acute myocardial infarction may result from an increase in myocardial <span class="chemical">oxygen</span> demand associated with <span class="chemical">cocaine</span> - induced increase in rate - pressure product . 