You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-(4-chlorophenyl)-N-[(1S)-1-(3,4-dimethoxyphenyl)ethyl]-5-methyltriazole-4-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C20H21ClN4O3
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