Code to check how many bundles are in an order

Hi! I am working on writing code for the Pinterest tag. I need to count the number of product bundles in the order (on the thank you page). Can you help with that expression?

Basically b/c the order quantity for a bundle of two products is three, I need to subtract 1 from the total quantity which I have already calculated with this code:

add_action('wp_head', 'wpb_hook_javascript1'); // Adds this to the head

function wpb_hook_javascript1() {
  if (is_page ( array('1751'))) { //Adds it to the specific page, in this case WooCommerce cart

	
// This calls the cart contents

$order_id_number = wc_get_order_id_by_order_key( $_GET['key'] );
$order = wc_get_order( $order_id_number );
$totalamount = $order->get_total();
	
$sumofitems = 0;	
foreach ( $order->get_items() as $item_id => $item ) {
   $quantity = $item->get_quantity();
   $sumofitems+=$quantity;
}
	
   
?> 
        <script>
  
		
			
  		pintrk('track', 'checkout', {  
        order_id: '<?php  echo  $order_id_number ?>',
		 value: '<?php echo $totalamount ?>', 
        order_quantity: '<?php echo $sumofitems ?>',
        currency: 'USD',
		em: '<?php echo wp_get_current_user()->user_email ?>'
			
			
  });
</script>