You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(15Z)-2-hydroxy-14,16-dimethyl-4-pyridin-2-yl-3,9,18-trioxa-6-azabicyclo[18.4.0]tetracos-15-ene-5,8,19-trione is the IUPAC name of a molecule. Please give its molecular formula.
user
C27H38N2O7
assistant