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: One hundred and twenty - two cycles of GEM - P were administered in total ( median 3 cycles ; range 1 - 6 ) .
### Output Text:
One hundred and twenty - two cycles of <span class="chemical">GEM</span> - P were administered in total ( median 3 cycles ; range 1 - 6 ) . 