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: After completion of the amifostine infusion , cisplatin 120 mg / m2 was administered over 30 minutes .
### Output Text:
After completion of the <span class="chemical">amifostine</span> infusion , <span class="chemical">cisplatin</span> 120 mg / m2 was administered over 30 minutes . 