You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(1,3-benzodioxol-5-ylmethyl)-3-[[3-[(dimethylamino)methyl]-4-fluorophenyl]methyl]-1,2-dimethylguanidine is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H27FN4O2
assistant