You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(5-chloro-2,3-dihydro-1,4-benzodioxin-7-yl)methyl]-1-ethyl-3-[(2-methoxyphenyl)methyl]guanidine;hydroiodide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H25ClIN3O3
assistant