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 (2S,4S)-4-[[5-chloro-6-(1H-indol-3-yl)imidazo[1,2-a]pyrazin-8-yl]amino]-N-methylpyrrolidine-2-carboxamide ?
user
C20H20ClN7O
assistant