class Node

{

int data;

Node left;

Node right;

Node(int data)

{

this.data=data;

left=right=null;

}

}

class BinaryTree{

Node root;

BinaryTree()

{

root = null;

}

BinaryTree(int data)

{

this.root=new Node(data);

}

int count(Node head)

{

if(head==null)

{

return 0;

}

return 1+count(head.left)+count(head.right);

}

}

class btreeCountNodes{

public static void main(String[] args) {

BinaryTree bt=new BinaryTree(2);

bt.root.left=new Node(3);

bt.root.right=new Node(5);

bt.root.left.right=new Node(9);

bt.root.right.left=new Node(7);

System.out.println(bt.count(bt.root));

}

}