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: On the contrary , among primary coronary artery bypass surgery patients , there were more acute myocardial infarctions and renal dysfunction in Group A ( 5 . 8 % vs 2 . 0 % , P = 0 . 027 ; 22 . 5 % vs 15 . 2 % , P = 0 . 036 , respectively ) .
### Output Text:
On the contrary , among primary coronary artery bypass surgery patients , there were more acute myocardial infarctions and renal dysfunction in Group A ( 5 . 8 % vs 2 . 0 % , P = 0 . 027 ; 22 . 5 % vs 15 . 2 % , P = 0 . 036 , respectively ) . 