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: Such treatment did not diminish the ADR antitumor activity in L1210 leukemia and in Ehrlich ascites tumor .
### Output Text:
Such treatment did not diminish the <span class="chemical">ADR</span> antitumor activity in L1210 leukemia and in Ehrlich ascites tumor . 