You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the compound with this IUPAC name N-[2-[(3S)-3-(4-chlorophenyl)-5-(1-methylpyrrol-2-yl)-3,4-dihydropyrazol-2-yl]-2-oxoethyl]-N-(2-methoxyethyl)acetamide ?
user
C21H25ClN4O3
assistant