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: Jaundice disappeared within 3 months but was followed by prolonged anicteric cholestasis marked by pruritus and high levels of alkaline phosphatase and gammaglutamyltransferase activities .
### Output Text:
Jaundice disappeared within 3 months but was followed by prolonged anicteric cholestasis marked by pruritus and high levels of alkaline phosphatase and gammaglutamyltransferase activities . 