You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 3-[4-(8-oxa-4,12-dithia-2-azatricyclo[7.3.0.03,7]dodeca-1(9),3(7),5,10-tetraen-2-ylmethoxy)phenyl]-2-propoxypropanoic acid by IUPAC nomenclature, provide its molecular formula.
user
C21H21NO5S2
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