You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[[[(2S)-butan-2-yl]amino]methyl]-1-[(4-methoxyphenyl)methyl]-6-methylindole-2-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H28N2O3
assistant