먼저
https://www.cnblogs.com/CV-life/p/10286037.html
두번째 부분
https://www.cnblogs.com/CV-life/p/10449028.html
기타 정보
<https://www.jianshu.com/p/e16ffb5b265d>
<https://blog.csdn.net/heyijia0327/article/details/47686523>
먼저
https://www.cnblogs.com/CV-life/p/10286037.html
두번째 부분
https://www.cnblogs.com/CV-life/p/10449028.html
기타 정보
<https://www.jianshu.com/p/e16ffb5b265d>
<https://blog.csdn.net/heyijia0327/article/details/47686523>