Problems with angledown dropdown

I am trying to select a city depending on a certain country with AngularJS.

PROBLEM: The problem is that when I select the country and then the city, the value of the country is erased from the input. Note: Do not delete the entire object until after selecting a city and selecting the country again, there if you delete the entire object.

Any solution would be very helpful. Thank you very much

So I have the country code

function CargarListaRMOPaises() {
  if ($route.current.loadedTemplateUrl.indexOf("Crear.html") > 0 ||
    $route.current.loadedTemplateUrl.indexOf("Editar.html") > 0) {
    RMOPaisService.getListaRMOPaises().then(function(e) {

      $scope.listaRMOPaises = e.data;

    });
  }
}

So I have the city code

/* Carga los paises dependiendo de la ciudad */
$scope.CargarPaisesPorCiudad = function() {
  if ($route.current.loadedTemplateUrl.indexOf("Crear.html") > 0 ||
    $route.current.loadedTemplateUrl.indexOf("Editar.html") > 0) {
    if ($scope.labelSeleccionePais) {
      $scope.disableCiudad = true;
    }

 RMOCiudadService.getListaRMOCiudadesPorPais($scope.solicitud.Ciudad.Pais).then(function(e) {
      $scope.disableCiudad = false;
      $scope.listaRMOCiudades = e.data;
    });
  }
};

This is the object when it is full

{
  "Id": 1,
  "Nombre": "Medellin",
  "IdPais": 1,
  "Pais": {
    "Id": 1,
    "Nombre": "Colombia"
  }
}