You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[3-ethyl-2-[(6-ethyl-5-sulfanylpyridin-2-yl)oxymethyl]phenyl]-1-hydrazinyl-1-methylurea The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H25N5O2S
assistant