diff --git a/inc/class-wooviet-vnd-paypal-standard.php b/inc/class-wooviet-vnd-paypal-standard.php
index 6f18f1b..a88d2f5 100644
--- a/inc/class-wooviet-vnd-paypal-standard.php
+++ b/inc/class-wooviet-vnd-paypal-standard.php
@@ -30,9 +30,10 @@ class WooViet_VND_Paypal_Standard {
 	 *
 	 * @param int $exchange_rate_to_vnd
 	 */
-	public function __construct( $exchange_rate_to_vnd = 22770 ) {
+	public function __construct( $exchange_rate_to_vnd = 22770, $paypal_currency ) {
 
-		$this->exchange_rate_to_vnd = $exchange_rate_to_vnd;
+		$this->exchange_rate_to_vnd = (int) $exchange_rate_to_vnd;
+		$this->paypal_currency = $paypal_currency;
 
 		// Add VND to the Paypal supported currencies
 		add_filter( 'woocommerce_paypal_supported_currencies', array( $this, 'add_vnd_paypal_valid_currency' ) );