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: Total cumulative doses were 36 or 60 g / m2 of ifosfamide ( six or 10 cycles of ifosfamide , vincristine , and dactinomycin [ IVA ] ) .
### Output Text:
Total cumulative doses were 36 or 60 g / m2 of <span class="chemical">ifosfamide</span> ( six or 10 cycles of <span class="chemical">ifosfamide , vincristine , and dactinomycin</span> [ <span class="chemical">IVA</span> ] ) . 