You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (5S)-N-(furan-2-ylmethyl)-7-propan-2-ylsulfonyl-6,8-dihydro-5H-imidazo[1,5-a]pyrazine-5-carboxamide into its molecular formula.
user
C15H20N4O4S
assistant