You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(cyclohexa-1,3-dien-1-ylmethyl)-8-fluoro-1,3,4,6,7,9a-hexahydropyrido[1,2-a]pyrazine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C15H21FN2
assistant