How to Hide Widget for Google Reviews Admin Menus

function plt_hide_widget_google_reviews_menus() {
	//Hide "Google Reviews".
	remove_menu_page('grw');
	//Hide "Google Reviews → Widgets".
	remove_submenu_page('grw', 'edit.php?post_type=grw_feed');
	//Hide "Google Reviews → Settings".
	remove_submenu_page('grw', 'grw-settings');
	//Hide "Google Reviews → Support".
	remove_submenu_page('grw', 'grw-support');
}

add_action('admin_menu', 'plt_hide_widget_google_reviews_menus', 11);

Where do I put this code?