You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[[4-amino-5-[5-(4-methylphenyl)pyrazolidin-3-yl]-1,2,4-triazol-3-yl]sulfanyl]-1-(4-nitrophenyl)ethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H21N7O3S
assistant