You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-[4-[2-[7-[5-chloro-2-(tetrazol-1-yl)phenyl]-5-oxo-2,3-dihydro-1H-indolizin-3-yl]-1H-imidazol-5-yl]phenyl]-3-ethylurea by IUPAC nomenclature, provide its molecular formula.
user
C27H24ClN9O2
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