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 dosage of methylprednisolone recommended by the NASCIS 3 is the highest dose of steroids ever being used during a 2 - day period for any clinical condition .
### Output Text:
The dosage of <span class="chemical">methylprednisolone</span> recommended by the NASCIS 3 is the highest dose of <span class="chemical">steroids</span> ever being used during a 2 - day period for any clinical condition . 