You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-cyclopropyl-9-methyl-N-(oxolan-2-ylmethyl)-[1,2,4]triazolo[4,3-c]quinazolin-5-amine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H21N5O
assistant