You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[[4-fluoro-2-(1,2,4-triazol-1-yl)phenyl]methyl]-3-hydroxy-4-oxospiro[7,8-dihydro-6H-pyrido[1,2-a]pyrimidine-9,1'-cyclobutane]-2-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H21FN6O3
assistant