You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[[2-(2-hydroxyethylsulfanyl)-4-oxopyrido[1,2-a]pyrimidin-3-yl]methylidene]-3-(oxolan-2-ylmethyl)-2-sulfanylidene-1,3-thiazolidin-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H19N3O4S3
assistant