You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1R,4S)-3-(4-ethylpiperazine-1-carbonyl)-7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C14H19N2O4-
assistant