class BST{
    private LinkedList data;
    private BST lc;
    private BST rc;
   

    public BST(){
	data = new Nil();
	lc = null;
	rc = null;
           }

    public BST copy(){
	BST aux = new BST();
	aux.data=data.copy();
	if (lc==null) aux.lc=null;
	else aux.lc=lc.copy();
	if (rc==null) aux.rc=null;
	else aux.rc=rc.copy();
	return aux;
    }
}