You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(3,4-dimethylphenyl)-3-[(R)-(4,5-dimethyl-1,2,4-triazol-3-yl)-phenylmethyl]urea The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H23N5O
assistant