You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-(2,3-dimethylphenyl)-1-(2-methylsulfonylethylsulfanyl)-[1,2,4]triazolo[4,3-a]quinazolin-5-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H20N4O3S2
assistant