Idea: I_love_myself
Solution: 77904333

Hello, Codeforces!

I'm glad to invite you to Codeforces Round 637 (Div. 1) - Thanks, Ivan Belonogov! and Codeforces Round 637 (Div. 2) - Thanks, Ivan Belonogov!, which will be held on Apr/23/2020 17:45 (Moscow time). The round will be rated for both divisions (I hope).

All problems were written and prepared by Aleksey Aleks5d Upirvitskiy, Alexey alexX512 Perevyshin and by me, Denis I_love_myself Sapozhnikov. Thanks to 300iq, voidmax, ashmelev, Akulyat, okwedook, Minnakhmetov, divanik, Zakoden, Jostic11, Nakinamo, 4qqqq и allisyonok for testing problems and good advice, isaf27 for round coordination and help with preparation and MikeMirzayanov for great systems Codeforces and Polygon.

You will be given 6 problems in both divisions and 2.5 hours to solve them. Please, read all the problems. Good luck, have fun and I wish everyone high ratings!

The scoring distribution will be announced closer to the beginning of the round.

Did you notice unusual in the title of the round? Here is the message from MikeMirzayanov:

With this round we want to convey fiery greetings and once again say thanks for the support to Ivan Belonogov Belonogov. And it’s not only about his significant gift on the 10th anniversary of the platform. Starting to participate in 2011, Ivan has come a long way from a participant in Div. 2 rounds to the international grandmaster, became the ICPC world champion as part of ITMO team. Such a striking motivational example of a success story! Thank you, Ivan!

UPD1: The scoring distribution will be:
Div1: 500-750-1250-1750-2250-3000
Div2: 500-1000-1500-1750-2250-2750

UPD2: Due to technical problems, the round is delayed by 10 minutes. Sorry!

UPD3: Editorial is published!

UPD4: This was our first round and we made mistakes wherever possible. Sorry for this. We decided to make Div1 round unrated, Div2 round is still rated. You can read more details in this post. We hope that you enjoyed solving interesting problems and did not pay attention to our mistakes.