You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-(3-oxo-[1,2,4]triazolo[4,3-a]pyridin-2-yl)ethyl]-N-(2-thiophen-2-ylethyl)piperidine-4-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H25N5O2S
assistant