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: 85 percent of patients with dyskinesias were relieved of symptoms , regardless of whether the pallidotomies were performed with the Gamma Knife or radiofrequency methods .
### Output Text:
85 percent of patients with dyskinesias were relieved of symptoms , regardless of whether the pallidotomies were performed with the Gamma Knife or radiofrequency methods . 