You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-ethyl-N-[6-[(2S)-1-[(2-methylphenyl)methyl]pyrrolidin-2-yl]pyrazin-2-yl]-1,3,4-thiadiazol-2-amine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H24N6S
assistant