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: Of the 715 patients tested with nimesulide 62 ( 8 . 6 % ) showed a positive test , while of 114 subjects submitted to the challenge with paracetamol , 13 ( 9 . 6 % ) did not tolerate this drug .
### Output Text:
Of the 715 patients tested with <span class="chemical">nimesulide</span> 62 ( 8 . 6 % ) showed a positive test , while of 114 subjects submitted to the challenge with <span class="chemical">paracetamol</span> , 13 ( 9 . 6 % ) did not tolerate this drug . 