You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-ethyl-5-[[3-(3-methoxypropyl)-4-oxo-2-sulfanylidene-1,3-thiazolidin-5-ylidene]methyl]-4-methyl-6-morpholin-4-yl-2-oxopyridine-3-carbonitrile is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H26N4O4S2
assistant