public static TreeNode commomAncestorWithBinarySearchTree(TreeNode p,TreeNode q,TreeNode root){
		if(root==null){
			return null;
		}
		if(root.data > p.data && root.data < q.data){
			return root;
		}
		TreeNode left = commomAncestorWithBinarySearchTree(p,q,root.left);
		if(left!=null){
			return left;
		}
		TreeNode right = commomAncestorWithBinarySearchTree(p,q,root.right);
		if(right != null){
			return right;
		}
		return null;
	}