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: Flestolol ( ACC - 9089 ) is a nonselective , competitive , ultra - short - acting beta - adrenergic blocking agent , without any intrinsic sympathomimetic activity .
### Output Text:
<span class="chemical">Flestolol</span> ( <span class="chemical">ACC - 9089</span> ) is a nonselective , competitive , ultra - short - acting beta - adrenergic blocking agent , without any intrinsic sympathomimetic activity . 