You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the compound with this IUPAC name 2-methyl-1-[(E)-pent-3-enyl]-3-spiro[3,4-dihydrochromene-2,1'-cyclopentane]-4-ylguanidine ?
user
C20H29N3O
assistant