public class BinaryTree {

	private Object data;
	private BinaryTree left, right;

	public BinaryTree(Object _data, BinaryTree _left, BinaryTree _right) {

		data = _data;
		left = _left;
		right = _right;
	}
	public BinaryTree(Object _data) {

		data = _data;
		left = null;
		right = null;
	}
	public boolean isEmpty() { return (data == null); }
	public int getData() { return (Integer)data; }

	public void add(Object _data) {
		add(this, _data);
	}
	public BinaryTree add(BinaryTree btn, Object _data) {

		if (btn == null) { btn = new BinaryTree(_data); }
		else if ((Integer)_data > btn.getData()) {
			btn.right = add(right, _data);
		}
		else {
			btn.left = add(left, _data);
		}
		return btn;
	}

	public static void main(String[] args) {

		BinaryTree btn = new BinaryTree(new Integer(30));
		btn.add(new Integer(60));
		btn.add(new Integer(20));

		System.out.println(btn.left.getData());
	}
}