Hello Codeforces!

I'm glad to announce that we will be having **Round 35** of **MathMash** today at **17: 00 UTC**. The round has been prepared by **Snpushpita** and DrSwad.

The round will consist of 8 problems, to be solved within 2 hours.

Points distribution for the problems are decided as `500-750-1250-1500-2000-2250-2500-2750`

We're inviting you all to join us in the contest. Hopefully we'll have a fun and successful round.

A few details about the contest:

In order to participate in the contest, you need to register first. Kindly follow

**this link**to do so. Registration deadline has been removed from the contests. So now, you can register at any time before the contest ends.I know this announcement is being placed in a coding website, but unfortunately using computer programs for MathMash contests is not allowed. We are trying to reward users' math skills with high ratings as there are not many sites that do this yet. We also try our best to set up the problems in such a way that any trivial brute force approach isn't supposed to work (for the mediocre/difficult problems).

**Time-penalty**is applicable for the contest: Each problem is given an appropriate number of points, which will be visible when the round starts. Participants will gain**that many points — the time penalty**after successfully submitting to a particular problem. The later the problem submission occurs, the more points being deducted due to time penalty.The round is

**rated**; which means that if you participate in the contest, your rating will be updated at the end of the round based on your rank in it. But you won't be considered as participating in the round if you don't submit any answer at all, even if you're registered for the contest.

a good platform for improving math skill.

C was pretty awesome problem.

Can you please tell the approach used for problem B ?

I just use a code in c++.

But I also need some mathematical approach.

I actually couldn't figure out anything. So please explain your logic or what kind of code did you use and how did that solve the problem ?

SpoilerThanks.

Please do not code to solve problems during contest. Such is not allowed and constitutes cheating, very serious offense.

I also not want to code. and I also want to know that should I write code or not but no one answers my question.

Please tell me, should I not write code for solve project Euler problem also?

Thanks for the suggestion.

Actually project euler problems are meant to be solved by code, but that's not the case for mathmash problems.

problem statement means that

and .

by fermat's little theorem for prime

p,so

and

we have that

so

and

, so

Thanks, did you get the last equation by chinese remainder theorem ?