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: Whereas 33 . 3 % of the patients with CIN were among those who received the proper dosage of CM , the percentage increased to 66 . 6 % among those who received larger doses , with a significant difference in the incidence of CIN related to the different dosages of CM ( p = 0 . 014 ) .
### Output Text:
Whereas 33 . 3 % of the patients with CIN were among those who received the proper dosage of <span class="chemical">CM</span> , the percentage increased to 66 . 6 % among those who received larger doses , with a significant difference in the incidence of CIN related to the different dosages of <span class="chemical">CM</span> ( p = 0 . 014 ) . 