You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[2-[(2R)-2-methyl-2,3-dihydroindol-1-yl]-2-oxoethyl] 3-methyl-2-nitrobenzoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H18N2O5
assistant