You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(5R)-5-ethyl-5-(4-fluorophenyl)-3-[(2R)-2-(4-fluorophenyl)-2-hydroxyethyl]imidazolidine-2,4-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H18F2N2O3
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