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: We attempted to identify all incident strokes in women ages 15 - 44 years during a 3 - year period using hospital admission and discharge records , emergency department logs , and payment requests for out - of - plan hospitalizations .
### Output Text:
We attempted to identify all incident strokes in women ages 15 - 44 years during a 3 - year period using hospital admission and discharge records , emergency department logs , and payment requests for out - of - plan hospitalizations . 