You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(6R)-N-hydroxy-1'-(2-methylpropyl)-2'-oxospiro[5,7,8,8a-tetrahydro-4aH-naphthalene-6,3'-pyrrolidine]-2-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H26N2O3
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