import java.util.Vector;

public class Tree extends Vector {

    public Tree () {
	super ();
	add ("bamboo");
    }

    public int size () {
	return super.size() - 1;
    }

    public int left (int i) {  return 2*i;  }
    public int right (int i) {  return 2*i + 1;  }
    public int parent (int i) {  return i/2;  }

    public void swap (int i, int j) {
	Object temp = get (i);
	set (i, get(j));
	set (j, temp);
    }

    public void print () {
	for (int i=0; i<=size(); i++) {
	    System.out.println (get (i));
	}
    }

}