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: An autoradiographic study was performed on male F - 344 rats fed diet containing FANFT at a level of 0 . 2 % and / or aspirin at a level of 0 . 5 % to evaluate the effect of aspirin on the increased cell proliferation induced by FANFT in the forestomach and bladder .
### Output Text:
An autoradiographic study was performed on male F - 344 rats fed diet containing <span class="chemical">FANFT</span> at a level of 0 . 2 % and / or <span class="chemical">aspirin</span> at a level of 0 . 5 % to evaluate the effect of <span class="chemical">aspirin</span> on the increased cell proliferation induced by <span class="chemical">FANFT</span> in the forestomach and bladder . 