Cannot parse problem on some pages.

[vuthanhtrung2010]

Some pages uses DMOJ but it is a modified UI and components.

This is the error I found. Example page: https://lqdoj.edu.vn/problem/primesnum

NOTE: I tested DMOJ pulling. It could pull from DMOJ based page. Eg: https://oj.vnoi.info/problem/codetour24_f_g