You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule ethyl 4-[4-[(5-ethyl-1,3,4-oxadiazol-2-yl)carbamoyl]phenyl]sulfonylpiperazine-1-carboxylate ?
user
C18H23N5O6S
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