You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-[2-[[5-(2-fluorophenyl)-4-methyl-1,2,4-triazol-3-yl]sulfanyl]propanoyl]-4H-1,4-benzoxazin-3-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H17FN4O3S
assistant