public boolean isLeaf(Node node)
  {
	  if(node.getLeft() == null && node.getRight() == null)
		  return true;
	  return false;
		   
  }
  public long sumTree(Node root)
  {
	 if(root == null)
		 return 0;
	 return root.getValue() + sumTree(root.getLeft()) + sumTree(root.getRight());
  }