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 administration of lamivudine to patients with HBV - related cirrhosis , like our present case , should be considered as an initial medical therapeutic option , especially in countries where liver transplantation is not reliably available .
### Output Text:
The administration of <span class="chemical">lamivudine</span> to patients with HBV - related cirrhosis , like our present case , should be considered as an initial medical therapeutic option , especially in countries where liver transplantation is not reliably available . 