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: CONCLUSIONS : Clinical outcomes with risperidone were equal to those with olanzapine , and response may be more stable .
### Output Text:
CONCLUSIONS : Clinical outcomes with <span class="chemical">risperidone</span> were equal to those with <span class="chemical">olanzapine</span> , and response may be more stable . 