You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl N-[(2S)-1-[(2S)-2-(4-bromo-3H-pyrrol-2-yl)pyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl]carbamate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C15H22BrN3O3
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