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: CONCLUSION : No quantitative evidence for narrowing of large cerebral arteries or qualitative angiographic evidence for distal narrowing or vasculitis could be found in patients who underwent angiography after aneurysmal SAH associated with cocaine use .
### Output Text:
CONCLUSION : No quantitative evidence for narrowing of large cerebral arteries or qualitative angiographic evidence for distal narrowing or vasculitis could be found in patients who underwent angiography after aneurysmal SAH associated with <span class="chemical">cocaine</span> use . 