You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[(2-cyclopentyloxypyridin-4-yl)methyl]-2-methyl-3-[(5-methylthiophen-2-yl)methyl]guanidine is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H26N4OS
assistant