You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[[(6S)-3-(1,3-benzodioxol-5-yl)-6,8-dihydro-5H-imidazo[2,1-c][1,4]oxazin-6-yl]methyl]-3-(4-fluorophenyl)urea is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H19FN4O4
assistant