You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule N-[4-[2-[4-(2-nitrophenyl)piperazin-1-yl]-2-oxoethyl]-1,3-thiazol-2-yl]furan-2-carboxamide into molecular formula.
user
C20H19N5O5S
assistant