You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(5Z)-5-benzylidene-3-(1-imidazo[1,2-a]pyridin-5-ylsulfanylbutyl)-1,3-thiazolidine-2,4-dione;hydrochloride is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H20ClN3O2S2
assistant