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: Development of levodopa - induced dyskinesias in parkinsonian monkeys may depend upon rate of symptom onset and / or duration of symptoms .
### Output Text:
Development of <span class="chemical">levodopa</span> - induced dyskinesias in parkinsonian monkeys may depend upon rate of symptom onset and / or duration of symptoms . 