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: No statistically significant changes in behavior or receptor binding were found in PD males with the exception of increased ( 3 ) H - MK - 801 binding in cortex .
### Output Text:
No statistically significant changes in behavior or receptor binding were found in PD males with the exception of increased ( 3 ) <span class="chemical">H</span> - <span class="chemical">MK - 801</span> binding in cortex . 