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: Given three times fluvoxamine had no effect on the immobilization time in the " behavioral despair " test in rats .
### Output Text:
Given three times <span class="chemical">fluvoxamine</span> had no effect on the immobilization time in the " behavioral despair " test in rats . 