You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-1-acetyl-N-[4-(1,3,4-oxadiazol-2-yl)phenyl]-2,3-dihydroindole-2-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H16N4O3
assistant