import java.util.ArrayList;
import java.util.List;

abstract class Component {

  protected String name;

  public Component(String name) {
    this.name = name;
  }

  public abstract void Add(Component c);

  public abstract void Remove(Component c);

  public abstract void GetChild(int depth);
}

class Leaf extends Component {

  public Leaf(String name) {
    super(name);
  }

  @Override
  public void Add(Component c) {
    System.out.println("Can not add to a leaf");
  }

  @Override
  public void Remove(Component c) {
    System.out.println("Can not remove from a leaf");
  }

  @Override
  public void GetChild(int depth) {
    String temp = " ";
    for (int i = 0; i < depth; i++) {
      temp += "-";
      System.out.println(temp + name);
    }
  }

}

class Composite extends Component {

  private List<Component> children = new ArrayList<>();

  public Composite(String name) {
    super(name);
  }

  @Override
  public void Add(Component c) {
    children.add(c);
  }

  @Override
  public void Remove(Component c) {
    children.remove(c);
  }

  @Override
  public void GetChild(int depth) {

    for (Component c : children) {
      c.GetChild(depth);
    }
  }

}

public class Main {

  public static void main(String args[]) {
    Composite root = new Composite("root");
    root.Add(new Leaf("Leaf A"));
    root.Add(new Leaf("Leaf B"));

    Composite compX = new Composite("Composite X");
    compX.Add(new Leaf("Leaf XA"));
    compX.Add(new Leaf("Leaf XB"));
    root.Add(compX);

    Composite compXY = new Composite("Composite XY");
    compXY.Add(new Leaf("Leaf XYA"));
    compXY.Add(new Leaf("Leaf XYB"));
    compX.Add(compXY);

    root.GetChild(3);
  }

}