You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1,5-dimethyl-2-phenyl-4-[(E)-(2,4,4-trioxo-4a,5,6,7,8,8a-hexahydrobenzo[b][1,4]oxathiin-3-ylidene)hydrazinylidene]pyrazol-1-ium-3-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H21N4O5S+
assistant