You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 2-chloro-4-[methyl(methylsulfonyl)amino]-N-[(4R)-2,2,7-trimethyl-3,4-dihydrochromen-4-yl]benzamide into molecular formula.
user
C21H25ClN2O4S
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