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: Nonsteroidal anti - inflammatory drug - induced cystitis is a poorly recognized and under - reported condition .
### Output Text:
Nonsteroidal anti - inflammatory drug - induced cystitis is a poorly recognized and under - reported condition . 