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: A single neurotoxic dose of methamphetamine induces a long - lasting depressive - like behaviour in mice .
### Output Text:
A single neurotoxic dose of <span class="chemical">methamphetamine</span> induces a long - lasting depressive - like behaviour in mice . 