You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(5S)-N-(2,5-dichlorophenyl)-2-(4-methylpiperidin-1-yl)-4,7-dioxo-3,5,6,8-tetrahydropyrido[2,3-d]pyrimidine-5-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H21Cl2N5O3
assistant