You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[(R)-(4-chlorophenyl)-pyrazolo[1,5-a]pyridin-5-ylmethyl]-2-oxoimidazolidine-4-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H16ClN5O2
assistant