You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[4-[[ethyl(propyl)amino]methyl]benzoyl]-2,3,3a,4,5,6,7,7a-octahydroindole-2-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H32N2O3
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