https://blog.faceutil.com/2017/03/23/msx-%eb%b2%a0%ec%9d%b4%ec%a7%81-%ec%9e%85%eb%ac%b8-2-basic-nyuumon-2-%ef%bd%8d%ef%bd%93%ef%bd%98%ef%bd%82%ef%bd%81%ef%bd%93%ef%bd%89%ef%bd%83%e5%85%a5%e9%96%80ii-th/