You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (1S,2S,3R,4R)-3-[[(1R)-1-[4-[(2S)-butan-2-yl]phenyl]ethyl]carbamoyl]bicyclo[2.2.1]heptane-2-carboxylic acid into its molecular formula.
user
C21H29NO3
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