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: Adverse events related to EPS occurred in 59 . 6 % of patients treated with haloperidol ( n = 99 ) monotherapy , whereas 26 . 5 % of patients treated with lithium ( n = 98 ) monotherapy experienced adverse events related to EPS .
### Output Text:
Adverse events related to EPS occurred in 59 . 6 % of patients treated with <span class="chemical">haloperidol</span> ( n = 99 ) monotherapy , whereas 26 . 5 % of patients treated with <span class="chemical">lithium</span> ( n = 98 ) monotherapy experienced adverse events related to EPS . 