How to Hide the "Post Status Notifier Lite" Admin Menu

function plt_hide_post_status_notifier_lite_menus() {
	//Hide the "Settings → Post Status Notifier Lite" menu.
	remove_submenu_page('options-general.php', 'post-status-notifier-lite');
}

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

Where do I put this code?