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 (3S,4S)-8-[6-amino-5-(2-amino-3-chloropyridin-4-yl)sulfanyl-3-ethenylpyrazin-2-yl]-3-methyl-2-oxa-8-azaspiro[4.5]decan-4-amine .
user
C20H26ClN7OS
assistant