Before I joined the contest "Codeforces Round 946 (Div. 3)", i had 1330 ratings. I recived 76 ratings on 21/5/2024 after this contest (1406)

But on 25/5, I check my account and see that my rank is become Pupil and have 1399. I don't know why?

Proof: https://i.imgur.com/5vYxQnA.png

I used to use C++14 to submit code but now I can't find C++14 language so anyone help me how to enable it?