How to Hide the "SmartAsset Captivate" Admin Menu

function plt_hide_captivate_by_smartasset_menus() {
	//Hide the "Settings → SmartAsset Captivate" menu.
	remove_submenu_page('options-general.php', 'smartasset_plugin');
}

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

Where do I put this code?