You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-tert-butyl-2-chloro-N-[(2-oxo-1,3-dihydroindol-5-yl)methyl]pyridine-3-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H20ClN3O2
assistant