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 experiment set up 1 : Memory deficit was found in Morris water maze test on 14 - 16 days after STZ ( ICV ; 3mg / Kg ) administration .
### Output Text:
In experiment set up 1 : Memory deficit was found in Morris water maze test on 14 - 16 days after <span class="chemical">STZ</span> ( ICV ; 3mg / Kg ) administration . 