Invert infinite menu direction

1

Hello people,
I have a little question. How can i change change direction of the infinite menu? I mean i go to the left, the menu will go to the right. i’m using this code

onClipEvent (load) {
	xcenter = 350;
	speed = 1/10;
	_x=50
	}
onClipEvent (enterFrame) {
	var distance = _root._xmouse-xcenter;
	if (_root.maskmc.hitTest(_root._xmouse, _root._ymouse)) {
		_x += (distance*speed);
		if (_x>50) {
			_x = 50;
		}
		if (_x<-2658) {
			_x = -2658;
		}
	}
}

is it possible to invert the _xmouse ?