You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-ethyl-N-[(3-fluoro-4-methoxyphenyl)methyl]-4-(1,2,4-triazol-1-ylmethyl)benzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H21FN4O2
assistant