You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(3,4-dihydro-2H-1,5-benzodioxepin-7-yl)-4-ethyl-5,6-dihydro-4H-1,3-thiazin-2-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H20N2O2S
assistant