You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-(2-ethyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[1,5-a]pyridin-8-yl)-3-(1-phenylcyclobutyl)urea by IUPAC nomenclature, provide its molecular formula.
user
C19H25N5O
assistant