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: Highly active antiretroviral therapy ( HAART ) has significantly reduced morbidity and mortality of acquired immunodeficiency syndrome ( AIDS ) , but has resulted in an increase in cardiac and skeletal myopathies .
### Output Text:
Highly active antiretroviral therapy ( HAART ) has significantly reduced morbidity and mortality of acquired immunodeficiency syndrome ( AIDS ) , but has resulted in an increase in cardiac and skeletal myopathies . 