You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(2,3-dihydroindol-1-yl)-3-[2-(2-hydroxyacetyl)-7-methyl-5,7-dihydro-4H-thieno[2,3-c]pyridin-6-yl]propan-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H24N2O3S
assistant