You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-(4-hydroxyphenyl)-1-methyl-2-methylsulfanyl-6,8-dihydro-5H-pyrido[2,3-d]pyrimidine-4,7-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H15N3O3S
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