You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule N-[1-[(2R,4S,5R)-4-[[(1S,3R,3aR)-3-[[methyl(diphenyl)silyl]methyl]-3a,4,5,6-tetrahydro-3H-pyrrolo[1,2-c][1,3,2]oxazaphosphol-1-yl]oxy]-5-[[bis(4-methoxyphenyl)-phenylmethoxy]methyl]-3-methoxyoxolan-2-yl]-2-oxopyrimidin-4-yl]-2-methylpropanamide into molecular formula.
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C54H61N4O9PSi
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