You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (5aS,9aS)-4-methyl-N,6-dipropyl-5a,7,8,9,9a,10-hexahydro-5H-pyrido[2,3-g]quinazolin-2-amine into its molecular formula.
user
C18H30N4
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