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: Complete resolution of symptoms within 1 - 4 days was accompanied by normalisation of ADC abnormalities .
### Output Text:
Complete resolution of symptoms within 1 - 4 days was accompanied by normalisation of ADC abnormalities . 