You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 6-[3-(5-ethyl-2,4-dihydroxyphenyl)-5-sulfanylidene-1H-1,2,4-triazol-4-yl]-4a,8a-dihydro-4H-1,4-benzoxazin-3-one .
user
C18H18N4O4S
assistant