You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[(2,5-difluorophenyl)methyl]-3-ethyl-2-[(3-fluoro-4-hydroxyphenyl)methyl]guanidine;hydroiodide is the IUPAC name of a molecule. Please give its molecular formula.
user
C17H19F3IN3O
assistant