You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule [3-octadecanoyloxy-2-[(6Z,9Z,12Z,15Z)-octadeca-6,9,12,15-tetraenoyl]oxypropyl] (27Z,30Z)-octatriaconta-27,30-dienoate into molecular formula.
user
C77H138O6
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