You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[(3,5-dimethyl-1-phenylpyrazol-4-yl)methyl]-2-methyl-3-(2-thiophen-2-ylethyl)guanidine is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H25N5S
assistant