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: A 45 - year - old man , with a 10 - year history of manic depression treated with lithium , was admitted with hyperosmolar , nonketotic coma .
### Output Text:
A 45 - year - old man , with a 10 - year history of manic depression treated with <span class="chemical">lithium</span> , was admitted with hyperosmolar , nonketotic coma . 