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: The results have shown that the degradation product p - choloroaniline is not a significant factor in chlorhexidine - digluconate associated erosive cystitis .
### Output Text:
The results have shown that the degradation product <span class="chemical">p - choloroaniline</span> is not a significant factor in <span class="chemical">chlorhexidine - digluconate</span> associated erosive cystitis . 