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: Methamphetamine or amphetamine levels were related to several psychopathology scores and the global hyperkinesia rating .
### Output Text:
<span class="chemical">Methamphetamine</span> or <span class="chemical">amphetamine</span> levels were related to several psychopathology scores and the global hyperkinesia rating . 