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: Angiotensin - converting enzyme inhibitor ( ACEI ) - induced angioedema was suspected , and anti - hypertensive medications were discontinued .
### Output Text:
Angiotensin - converting enzyme inhibitor ( ACEI ) - induced angioedema was suspected , and anti - hypertensive medications were discontinued . 