You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(E)-3-amino-2-[2-[[4-benzyl-5-(2-methylfuran-3-yl)-1,2,4-triazol-3-yl]sulfanyl]acetyl]but-2-enenitrile is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H19N5O2S
assistant