public class TreeNode {
	
	private String item;
	private TreeNode left;
	private TreeNode right;
	
	// leaf
	public TreeNode(String item){
	}

	// unary tree, left gets the child tree
	public TreeNode(String item, TreeNode child){
	}
	
	// binary tree
	public TreeNode(String item, TreeNode left, TreeNode right){
	}
	
	String getItem(){
		return "";
	}
	
	TreeNode getLeft(){
		return null;
	}
	
	TreeNode getRight(){
		return null;
	}
	
	public String toString(){
		if(right == null)
			if(left == null)
				return "leaf " + item;
			else
				return "unary " + item;
		else
			return "binary " + item;
		
	}
	
	public static void main(String[] args){
		
		TreeNode tn1 = new TreeNode("true");
		TreeNode tn2 = new TreeNode("false");
		TreeNode atree = new TreeNode("and",tn1,tn2);
		
		
		System.out.println("and tree: " + atree);
		System.out.println("  left:  " + atree.getLeft());
		System.out.println("  right: " + atree.getRight());
		
		TreeNode tn3 = new TreeNode("false");
		TreeNode ntree = new TreeNode("not",tn3);
		System.out.println("not tree: " + ntree);
		System.out.println("  left:  " + ntree.getLeft());		
	}
	
}