// Class to store a single node of a binary tree

public class TreeNode<E> {
   public E data;
   public TreeNode<E> left;
   public TreeNode<E> right;
   
   // Constructs a node with the given data and left and right subtrees
   public TreeNode(E data, TreeNode<E> left, TreeNode<E> right) {
      this.data = data;
      this.left = left;
      this.right = right;
   }

   // Constructs a leaf node with the given data   
   public TreeNode(E data) {
      this(data, null, null);
   }
}