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: Symptoms such as euphoria , emotional lability and puerile attitude noted in the patient were diagnosed as organic personality syndrome according to the criteria defined in the DSM - III - R .
### Output Text:
Symptoms such as euphoria , emotional lability and puerile attitude noted in the patient were diagnosed as organic personality syndrome according to the criteria defined in the DSM - III - R . 