You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[2-chloro-4-(dimethylamino)phenyl]-6-[[(1R,2S)-2-ethoxy-2,3-dihydro-1H-inden-1-yl]amino]-1-ethyl-5-methylpyrazin-2-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C26H31ClN4O2
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