You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 3-[2-[5b,8,11a-trimethyl-2-oxo-1-propan-2-yl-3a-[2-(pyridine-2-carbonylamino)ethyl]-4,5,5a,6,7,7a,8,9,10,11,11b,12,13,13a-tetradecahydro-3H-cyclopenta[a]chrysen-9-yl]acetyl]-2-methylcyclobutane-1-carboxylic acid .
user
C43H60N2O5
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