You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(7Z)-3-(4-iodophenyl)-7-(1-methyl-2-oxoindol-3-ylidene)-2,4-dihydro-[1,3]thiazolo[3,2-a][1,3,5]triazin-6-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H15IN4O2S
assistant