You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[[3-[5-[(4-chlorophenoxy)methyl]-1H-pyrazol-3-yl]pyrrolidin-1-yl]methyl]pyridine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H21ClN4O
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