You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl (2E)-11-oxapentacyclo[10.8.0.03,7.04,9.015,20]icosa-1(12),2,5,13,15,17,19-heptaene-8-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H20O3
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