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: METHODS : A retrospective chart analysis and a review of the organ transplant database identified 51 patients ( 43 men and 8 women ) transplanted for benign HBV - related cirrhotic diseases between June 2002 and December 2004 who had survived more than 3 months .
### Output Text:
METHODS : A retrospective chart analysis and a review of the organ transplant database identified 51 patients ( 43 men and 8 women ) transplanted for benign HBV - related cirrhotic diseases between June 2002 and December 2004 who had survived more than 3 months . 