You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-methyl-N-[3-(5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-2-yl)phenyl]cyclopropane-1-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C18H21N3O
assistant