You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-benzylsulfanyl-6-[(2,4-dichlorophenyl)methylamino]-2-methylsulfanylpyrimidine-5-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H17Cl2N3O2S2
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