You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-hydroxy-9-methyl-2-oxo-6-phenyl-15-thia-1,5,7-triazatetracyclo[8.7.0.03,8.012,16]heptadeca-3,5,7,12(16),13-pentaene-14-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C21H18N4O3S
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