You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(1,4-dioxaspiro[4.6]undecan-3-ylmethyl)-1-(2-pyridin-2-ylethyl)guanidine;hydroiodide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H29IN4O2
assistant