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: RESULTS : Study results showed that myoclonus incidence was 85 % , 40 % , 70 % , and 25 % in Group NP , Group F , Group M , and Group FM , respectively , and were significantly lower in Group F and Group FM .
### Output Text:
RESULTS : Study results showed that myoclonus incidence was 85 % , 40 % , 70 % , and 25 % in Group NP , Group F , Group M , and Group FM , respectively , and were significantly lower in Group F and Group FM . 