You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (6R)-N-(2-ethoxyphenyl)-6-(4-fluorophenyl)-6,7-dihydro-4H-triazolo[5,1-c][1,4]oxazine-3-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C20H19FN4O3
assistant