You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-ethyl-1-[(3-phenyl-4,5-dihydro-1,2-oxazol-5-yl)methyl]-3-[3-(trifluoromethyl)phenyl]urea is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H20F3N3O2
assistant