You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-(1-hydroxyethyl)-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-5-yl]-3-(4-methyl-1,3-thiazol-5-yl)propan-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H20N4O2S
assistant