You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(6-oxospiro[1,3,4,10b-tetrahydropyrido[2,1-a]isoindole-2,2'-1,3-dithiolane]-10-yl)-3-pyrazin-2-ylurea The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H19N5O2S2
assistant