You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-ethyl-2-[(5-fluoro-3-methyl-1-benzofuran-2-yl)methyl]-3-(1-methyl-6-oxopiperidin-3-yl)guanidine is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H25FN4O2
assistant