You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[5-[hydroxy-[2-[(4-methoxyphenyl)methylidene]hydrazinyl]methylidene]-4-imino-3-phenyl-1,3-thiazolidin-2-ylidene]propanedinitrile is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H16N6O2S
assistant