You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-ethyl-2-[(3-ethyl-1,2-oxazol-5-yl)methyl]-3-[(5-ethylthiophen-2-yl)methyl]guanidine;hydroiodide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C16H25IN4OS
assistant