You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named N-[(4-cyanophenyl)methyl]-2-[(1-methylsulfonylcyclopropyl)methyl]-1,6-dioxo-3,4-dihydropyrido[1,2-a]pyrazine-7-carboxamide by IUPAC nomenclature, provide its molecular formula.
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C22H22N4O5S
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