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: She was re - induced with nelarabine 1500 mg / m ( 2 ) on days 1 , 3 , and 5 with 1 dose of IT cytarabine 100 mg on day 2 as central nervous system ( CNS ) prophylaxis .
### Output Text:
She was re - induced with <span class="chemical">nelarabine</span> 1500 mg / m ( 2 ) on days 1 , 3 , and 5 with 1 dose of IT <span class="chemical">cytarabine</span> 100 mg on day 2 as central nervous system ( CNS ) prophylaxis . 