You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 2-[3-[(4-ethyl-5-pyridin-4-yl-1,2,4-triazol-3-yl)sulfanyl]propyl]isoindole-1,3-dione .
user
C20H19N5O2S
assistant