EObject _eContainer_1 = ((Chapter)identifiable).eContainer();
EObject _eContainer_2 = _eContainer_1.eContainer();
if ((_eContainer_2 instanceof Document)) {
EObject _eContainer_3 = ((Chapter)identifiable).eContainer();
EObject _eContainer_4 = _eContainer_3.eContainer();
EList<EObject> _eContents = _eContainer_4.eContents();
EObject _eContainer_5 = ((Chapter)identifiable).eContainer();
int _indexOf = _eContents.indexOf(_eContainer_5);
_xifexpression_1 = ("_" + Integer.valueOf(_indexOf));
} else {
_xifexpression_1 = "";