You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[3-(2,4-dimethylphenyl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazol-2-yl]ethanamine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C16H21N3
assistant