You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[2-[4-[2-(azepan-1-yl)-2-oxoethyl]piperazin-1-yl]-2-oxoethyl]-2-methylbutanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H34N4O3
assistant