You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (1R,2R,3S,4S)-3-(4-phenylpiperazine-1-carbonyl)-7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C18H19N2O4-
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