You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-N-cyclohexyl-2-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-5-fluoropyrimidine-2,4-diamine is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H21FN4O2
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