You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
actinium;(4R,5R)-6-ethyl-5-[(2S,4S,5R)-6-ethyl-3,4,5-trimethyloxan-2-yl]oxy-4-methyloxane-2,3-diol is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H34AcO5
assistant