You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(2,3-dimethoxyphenyl)methyl]-1-ethyl-3-[(5-ethyl-1,3-thiazol-2-yl)methyl]guanidine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H26N4O2S
assistant