https://blog.wongcw.com/2021/11/17/lightcounting%ef%bc%9a%e4%be%9b%e6%87%89%e9%8f%88%e7%9f%ad%e7%bc%ba%e6%88%96%e5%b0%87%e6%8c%81%e7%ba%8c%e5%88%b02022%e5%b9%b4%e5%ba%95/