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: SNP is authorized for clinical use in USA and UK , and ATP is clinically used in other countries such as Japan .
### Output Text:
<span class="chemical">SNP</span> is authorized for clinical use in USA and UK , and <span class="chemical">ATP</span> is clinically used in other countries such as Japan . 