You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-propyl-3-(4-pyrimidin-2-ylpiperazin-1-yl)-4-thiophen-2-ylpyrrole-2,5-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H21N5O2S
assistant