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: RAMH per se showed significant reduction in locomotor time , distance traveled and average speed but THP ( 15 mg / kg i . p . ) per se had no effect on these parameters .
### Output Text:
<span class="chemical">RAMH</span> per se showed significant reduction in locomotor time , distance traveled and average speed but <span class="chemical">THP</span> ( 15 mg / kg i . p . ) per se had no effect on these parameters . 