You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1,1-dioxo-7-thiophen-2-yl-1,4-thiazepan-4-yl)-(4-phenoxyphenyl)methanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C22H21NO4S2
assistant