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: The beneficial effect of Adriamycin appears obvious and might be related to the drug itself , the early and repeated instillations after TUR , or both .
### Output Text:
The beneficial effect of <span class="chemical">Adriamycin</span> appears obvious and might be related to the drug itself , the early and repeated instillations after TUR , or both . 