How to Hide the "Loader CSS3" Admin Menu

function plt_hide_loader_css3_menus() {
	//Hide the "Settings → Loader CSS3" menu.
	remove_submenu_page('options-general.php', 'loader_css3_settings');
}

add_action('admin_menu', 'plt_hide_loader_css3_menus', 11);

Where do I put this code?