REASON If you see a dollar sign is printing unexpectedly in questions of Codeforces , this is because of Codeforces uses the Mathjax library to format mathematical equations, and if you view network traffic($) on your browser, you will see that when trying to get the Mathjax library it is not getting anything back .

SOLUTION-1

You can solve it by opening :
https://cdn-mathjax.codeforces.com/MathJax.js?config=TeX-AMS_HTML-full Keeping the tab open next to your Codeforces account and refresh your page.

SOLUTION-2 You can use Firefox browser to overcome it.