**내가 돌아왔다!** (Hello, Codeforces!)

I am thrilled to introduce you to Codeforces Round #633. Followings are basic information:

- This contest will take place on Apr/12/2020 17:05 (Moscow time).
- The round is
**rated for all participants**who can understand this announcement. There will be two divisions. - There are
**5 problems**in each division and you will have**2 hours**to solve it. - Score distribution will be announced later.

Followings are contributors:

**Authors**: McDic (All Div.2 problems and Div.1 D), tzuyu_chou (Div.1 E)**Coordinator**: antontrygubO_o**Testers**:**Phase 1**(When this round was supposed to be Div.2): dorijanlendvaj, SoulTch, pajenegod, AryaPawn, Rahul, mcdx9524, 300iq, Nemo, tfg**Phase 2**(Before we knew that old Div1D can be easily googled): Um_nik, Ari, benson1029, khulegu, Sad_reacts_only, TselmegKh**Phase 3**(Before few days to the round): mohammedehab2002, Kuroni, xuanquang1999, Maripium, MrDecomposition

**CF Admins**: Thanks to MikeMirzayanov and his team for maintaining Codeforces and Polygon. I would like to say same sentence again as I said in my last round's announcement. Polygon is super great platform to prepare sports programming contest.

Followings are some fun things:

- antontrygubO_o is the most intense coordinator I have ever met. He rejected lots of my problems. Some example of rejection comments are below:
*This problem is too standard.**Don't ask people about theorem and formula.**This problem is appeared in recent ptz camp with higher constraints.**I don't like it.**Rock Scissor Paper makes statement messy, because some people don't know about it.**D2A should be easier than this one.**I've found generalized version of this problem in POI.**Isn't this obvious?**Your proof is wrong.**This problem is not very interesting.**This is too***(censored)**.

- After lots of rejections, I tried my best to make problems to be interesting. I hope you like at least some of my problems.
- This round was originally supposed to be rated for Div.2 only. However, after we completed Phase 1 testing, we found that my round is too hard for Div.2, so we added more problems and made this round to be Div.1.
- In this round, statements will be even shorter than last contest.
- Even for some of problems which my coordinator approved, there were critical issues that made problems to be excluded. I will introduce some of my rejected problems which won't be used anymore in another post, after this contest ends.

I hope everyone can enjoy my third contest. Thanks in advance!

Followings are updates:

- Score Distribution:
**Div.1: 500 1000 1500 2000 2750****Div.2: 500 750 1250 1750 2250**

- I am sorry for such Div2C/Div1A statement issue. We fixed that immediately after few minutes to the round, but we should have announced it.
- Editorial is posted: https://codeforces.com/blog/entry/75913
- I opened new mashup for excluded problems. These problems are originally approved by antontrygubO_o but excluded for some reasons.
**Binomial Determinant**is old Div1D. We found this problem on google so we removed this.**Divisible Xor**is old Div1A. But since we made 3 xor problems, we removed this one.

Followings are winners:

<Div.1>

<Div.2>