You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 1-[[4-chloro-3-[(4-ethylsulfonylpiperazin-1-yl)methyl]phenyl]methyl]-1-(6-methylpyridin-3-yl)urea ?
user
C21H28ClN5O3S
assistant