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: Replication - competent HBV strains with sG145R or sP120T and LAM resistance ( rtM204I or rtL180M / rtM204V ) were generated on an HBeAg - positive and an HBeAg - negative background with precore ( PC ) and basal core promoter ( BCP ) mutants .
### Output Text:
Replication - competent HBV strains with sG145R or sP120T and <span class="chemical">LAM</span> resistance ( rtM204I or rtL180M / rtM204V ) were generated on an <span class="chemical">HBeAg</span> - positive and an <span class="chemical">HBeAg</span> - negative background with precore ( PC ) and basal core promoter ( BCP ) mutants . 