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: More patients were ( completely , very or somewhat ) satisfied 2 h after treatment with rizatriptan ( 69 . 8 % ) than at 2 h after treatment with ergotamine / caffeine ( 38 . 6 % , p < or = 0 . 001 ) .
### Output Text:
More patients were ( completely , very or somewhat ) satisfied 2 h after treatment with <span class="chemical">rizatriptan</span> ( 69 . 8 % ) than at 2 h after treatment with <span class="chemical">ergotamine</span> / <span class="chemical">caffeine</span> ( 38 . 6 % , p < or = 0 . 001 ) . 