You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethane;[(3R)-3-(prop-2-ynylamino)-2,3-dihydro-1H-inden-5-yl] N-ethyl-N-(hydroxymethyl)carbamate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H26N2O3
assistant