You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-[[[2-(4-chlorophenyl)ethylamino]-(2-phenylethylamino)methylidene]amino]-N,N-dimethylacetamide by IUPAC nomenclature, provide its molecular formula.
user
C21H27ClN4O
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