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: An allergic reaction consisting of angioneurotic edema secondary to continuous infusion 5 - fluorouracil occurred in a patient with recurrent carcinoma of the oral cavity , cirrhosis , and cisplatin - induced impaired renal function .
### Output Text:
An allergic reaction consisting of angioneurotic edema secondary to continuous infusion <span class="chemical">5 - fluorouracil</span> occurred in a patient with recurrent carcinoma of the oral cavity , cirrhosis , and <span class="chemical">cisplatin</span> - induced impaired renal function . 