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: In one patient , the tinnitus was almost completely abolished , but in all the nine patients the decompensated tinnitus changed to a compensated one .
### Output Text:
In one patient , the tinnitus was almost completely abolished , but in all the nine patients the decompensated tinnitus changed to a compensated one . 