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 sumBT(Node head)

{

if(head==null)

{

return 0;

}

return head.data+ sumBT(head.left)+sumBT(head.right);

}

//method 2

static int sum=0;

public int sumBT1(Node root)

{

sum=0;

return sum(root);

}

public int sum(Node root){

if(root == null)

return 0;

sum(root.left);

sum(root.right);

sum += root.data;

return sum;

}

}

class treeSum{

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.sumBT(bt.root));

System.out.println(bt.sumBT1(bt.root));

//2nd binary tree

BinaryTree bt1=new BinaryTree(2);

bt1.root.left=new Node(3);

bt1.root.right=new Node(10);

bt1.root.left.right=new Node(9);

bt1.root.right.left=new Node(6);

System.out.println(bt1.sumBT(bt1.root));

System.out.println(bt1.sumBT1(bt1.root));

}

}