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: FINDINGS : A 28 - year - old man suffering from idiopathic epilepsy with generalized seizures was treated with LEV ( 3000 mg ) added to valproate ( VPA ) ( 2000 mg ) .
### Output Text:
FINDINGS : A 28 - year - old man suffering from idiopathic epilepsy with generalized seizures was treated with <span class="chemical">LEV</span> ( 3000 mg ) added to <span class="chemical">valproate</span> ( <span class="chemical">VPA</span> ) ( 2000 mg ) . 