How to Hide Official StatCounter Plugin Admin Menus

function plt_hide_official_statcounter_plugin_for_wordpress_menus() {
	//Hide the "Dashboard → StatCounter Stats" menu.
	remove_submenu_page('index.php', 'statcounter');
	//Hide the "Plugins → StatCounter Admin" menu.
	remove_submenu_page('plugins.php', 'statcounter_admin');
	//Hide the "Settings → StatCounter" menu.
	remove_submenu_page('options-general.php', 'StatCounter-Wordpress-Plugin.php');
}

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

Where do I put this code?