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: DESIGN : A prospective study to monitor indinavir - related nephrotoxicity in a cohort of 30 human immunodeficiency virus type 1 - infected children treated with indinavir .
### Output Text:
DESIGN : A prospective study to monitor <span class="chemical">indinavir</span> - related nephrotoxicity in a cohort of 30 human immunodeficiency virus type 1 - infected children treated with <span class="chemical">indinavir</span> . 