You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[(3S,4S)-3-hydroxy-4-pyrrolidin-1-ylpyrrolidin-1-yl]-2-piperidin-4-ylethanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H27N3O2
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