You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[2-methoxy-4-[(5S)-1-methyl-2,4,7-trioxo-6,8-dihydro-5H-pyrimido[4,5-d]pyrimidin-5-yl]phenoxy]acetonitrile The above is the IUPAC name of a molecule. Write its molecular formula.
user
C16H15N5O5
assistant