You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[2-[(24Z,27Z,30Z,33Z,36Z,39Z)-dotetraconta-24,27,30,33,36,39-hexaenoyl]oxy-3-[(15Z,18Z)-hexacosa-15,18-dienoyl]oxypropoxy]-2-[2-(trimethylazaniumyl)ethoxy]acetate is the IUPAC name of a molecule. Please give its molecular formula.
user
C78H137NO8
assistant