You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (2R)-2-(3-chloro-4-methylsulfonylphenyl)-3-cyclopentyl-N-[5-(2-methoxyphenyl)pyrazin-2-yl]propanamide .
user
C26H28ClN3O4S
assistant