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: Those patients receiving AmB and spironolactone required significantly less potassium supplementation to maintain their plasma potassium within the normal range ( P = 0 . 022 ) .
### Output Text:
Those patients receiving <span class="chemical">AmB</span> and <span class="chemical">spironolactone</span> required significantly less <span class="chemical">potassium</span> supplementation to maintain their plasma <span class="chemical">potassium</span> within the normal range ( P = 0 . 022 ) . 