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: With 2 - drug therapy , mean total cholesterol decreased 22 % from 255 to 200 mg / dl , triglyceride levels decreased 35 % from 236 to 154 mg / dl , LDL cholesterol decreased 26 % from 176 to 131 mg / dl , and the total cholesterol / HDL cholesterol ratio decreased 24 % from 7 . 1 to 5 . 4 , all p less than or equal to 0 . 0001 .
### Output Text:
With 2 - drug therapy , mean total <span class="chemical">cholesterol</span> decreased 22 % from 255 to 200 mg / dl , <span class="chemical">triglyceride</span> levels decreased 35 % from 236 to 154 mg / dl , LDL <span class="chemical">cholesterol</span> decreased 26 % from 176 to 131 mg / dl , and the total <span class="chemical">cholesterol</span> / HDL <span class="chemical">cholesterol</span> ratio decreased 24 % from 7 . 1 to 5 . 4 , all p less than or equal to 0 . 0001 . 