You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl 3-[(E)-[(3aR,4S,5S,6aR)-5-hydroxy-4-[(E)-1-hydroxy-4-methyloct-1-en-6-ynyl]-3,3a,4,5,6,6a-hexahydro-1H-pentalen-2-ylidene]amino]oxypropanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H31NO5
assistant