You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[4-[(4-acetylphenyl)-[2-(trifluoromethyl)-1,3-oxazol-5-yl]methyl]phenyl]ethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H16F3NO3
assistant