You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule (1E)-1-[(4-fluorophenyl)methylidene]-3-[1-(morpholin-4-ylmethyl)-2,3-dioxoindol-5-yl]urea into molecular formula.
user
C21H19FN4O4
assistant