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: RATIONALE : Ecstasy ( MDMA ) is a psychostimulant drug which is increasingly associated with psychobiological dysfunction .
### Output Text:
RATIONALE : <span class="chemical">Ecstasy</span> ( <span class="chemical">MDMA</span> ) is a psychostimulant drug which is increasingly associated with psychobiological dysfunction . 