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: Here we show that the recently reported ability of L - dihydroxyphenylalanine to reverse the protective effect of alpha - methyl - para - tyrosine on METH - induced DA neurotoxicity is also confounded by drug effects on body temperature .
### Output Text:
Here we show that the recently reported ability of <span class="chemical">L - dihydroxyphenylalanine</span> to reverse the protective effect of <span class="chemical">alpha - methyl - para - tyrosine</span> on <span class="chemical">METH</span> - induced <span class="chemical">DA</span> neurotoxicity is also confounded by drug effects on body temperature . 