You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[4-[(4-ethynylphenyl)methyl]piperazin-1-yl]-[3-(methylsulfanylamino)pyrazol-1-yl]methanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H21N5OS
assistant