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 Group II , P did not prevent gentamicin - ARF ( maximal decrease in CCr at day 9 . 89 % , P less than 0 . 001 ; peak lysozymuria , 1863 + / - 321 micrograms / day ; and tubular necrosis score , 3 . 9 + / - 0 . 1 ) .
### Output Text:
In Group II , <span class="chemical">P</span> did not prevent <span class="chemical">gentamicin</span> - ARF ( maximal decrease in CCr at day 9 . 89 % , <span class="chemical">P</span> less than 0 . 001 ; peak lysozymuria , 1863 + / - 321 micrograms / day ; and tubular necrosis score , 3 . 9 + / - 0 . 1 ) . 