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: He was referred to us for neurological evaluation because he had difficulty in getting up from squatting position and was suspected to have myositis .
### Output Text:
He was referred to us for neurological evaluation because he had difficulty in getting up from squatting position and was suspected to have myositis . 