You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule (2S)-2-(2,4-dimethyl-5-phenylimidazo[1,5-b]pyridazin-7-yl)sulfanyl-2-phenylacetamide into molecular formula.
user
C22H20N4OS
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