You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[4-(2-hydroxy-5-methylphenyl)sulfonylpiperazin-1-yl]-[2-(1-methylpyrazol-4-yl)-1,3-thiazol-4-yl]methanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H21N5O4S2
assistant