https://blog.faceutil.com/2020/05/28/%ec%9b%8c%ed%81%ac-%ec%9c%a0%ec%a6%88%eb%a7%b5-rpg-%ec%95%84%ec%9e%90%ed%81%ac%ec%9d%98-%ea%b2%80%ed%88%ac%ec%82%ac%eb%93%a4-1-2-ij/