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: In the following report , a 65 - year - old critically ill patient with a suspected history of HITT was administered argatroban for anticoagulation on bypass during heart transplantation .
### Output Text:
In the following report , a 65 - year - old critically ill patient with a suspected history of HITT was administered <span class="chemical">argatroban</span> for anticoagulation on bypass during heart transplantation . 