You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(6-methoxy-2,3-dihydro-1,4-benzoxathiin-7-yl)-3-(2,4,6-trimethoxyphenyl)prop-2-en-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H22O6S
assistant