You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-methyl-7-[6-[3-(6-methylpyridazin-3-yl)oxycyclobutyl]oxypyridin-3-yl]pyrido[4,3-b]indole is the IUPAC name of a molecule. Please give its molecular formula.
user
C26H23N5O2
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