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Educational Codeforces Round 66 [Rated for Div. 2]
Difference between en3 and en4, changed 76 character(s)
Hello Codeforces!↵

On [contest_time:1175] [contest:1175] will start.↵

Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://codeforces.com/blog/entry/51208">blog post</a>.↵
 ↵
This round will be **rated for the participants with rating lower than 2100**. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.↵
 ↵
You will be given **7 problems** and **2 hours** to solve them.↵
 ↵
The problems were invented and prepared by Roman [user:Roms,2019-06-04] Glazov, Adilbek [user:adedalic,2019-06-04] Dalabaev, Vladimir [user:Vovuh,2019-06-04] Petrov, Ivan [user:BledDest,2019-06-04] Androsov, Maksim [user:Ne0n25,2019-06-04] Mescheryakov and me. Also huge thanks to Mike [user:MikeMirzayanov,2019-06-04] Mirzayanov for great systems Polygon and Codeforces.↵

Good luck to all participants!↵

UPD:↵

Our friends at Harbour.Space also have a message for you:↵

_Codeforces! What is the next step in your development?_↵

_We understand all about doing things by yourself &mdash; after all, we are a startup university, and our student body is exceptional in part because of it’s made up of people who didn’t wait for anyone to show them the way._↵

_If this is you, you belong at Harbour.Space. The purpose of our University is to create a global community of these kinds of people, regardless of age or nationality, because when you’re working by yourself, you can change for the better, but when you work with others, you can change the world._ ↵


_If you believe you have what it takes, we want you!_ ↵

_The curriculum is part of what makes the modules so special, and the other half? Our outstanding teachers who are leaders in their own respective industries._↵

![ ](/predownloaded/d4/f4/d4f4e95832e66c288374543d7e3984ba36bab99d.png)↵

_Our scholarships are set in such a way that doesn’t require additional applications &mdash; we believe in merit and potential, and so what you put in your application to the university will be our criteria._↵

_**You could be just the diamond we’re looking for, but you’ll never know unless you apply!**_ ↵

<center style="margin:2.5em;">↵
<a href="https://harbour.space/admissions/scholarship?utm_source=codeforces&utm_medium=partners" style="text-decoration:none; font-size:18px; background-color:#523996; color:white; font-weight:bold; padding:0.5em 1em;">APPLY NOW&rarr;</a>↵
</center>↵

Congratulations to the winners:↵
<table class='bordertable'>↵
<tbody>↵
<tr>↵
<th>Rank</th>↵
<th>Competitor</th>↵
<th>Problems Solved</th>↵
<th>Penalty</th>↵
</tr>↵
<tr>↵
<td>1</td>↵
<td>[user:mango_lassi, 2019-06-05]</td>↵
<td>6</td>↵
<td>145</td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:E869120, 2019-06-05]</td>↵
<td>6</td>↵
<td>148</td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:kefaa2, 2019-06-05]</td>↵
<td>6</td>↵
<td>154</td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:egor.lifar, 2019-06-05]</td>↵
<td>6</td>↵
<td>154</td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:Aria, 2019-06-05]</td>↵
<td>6</td>↵
<td>157</td>↵
</tr>↵
</tbody>↵
</table>↵


Congratulations to the best hackers:↵
<table class='bordertable'>↵
<tbody>↵
<tr>↵
<th>Rank</th>↵
<th>Competitor</th>↵
<th>Hack Count</th>↵
</tr>↵
<tr>↵
<td>1</td>↵
<td>[user:Radewoosh, 2019-06-05]</td>↵
<td><b><font color="green">97</font></b><b>:<font color="red">-19</font></b></td></td>↵
</tr>↵
<tr>↵
<td>2</td>↵
<td>[user:test_hack, 2019-06-05]</td>↵
<td><b><font color="green">56</font></b><b>:<font color="red">-37</font></b></td></td>↵
</tr>↵
<tr>↵
<td>3</td>↵
<td>[user:alvinvaja, 2019-06-05]</td>↵
<td><b><font color="green">30</font></b><b>:<font color="red">-10</font></b></td></td>↵
</tr>↵
<tr>↵
<td>4</td>↵
<td>[user:AryaKnight, 2019-06-05]</td>↵
<td><b><font color="green">48</font></b><b>:<font color="red">-48</font></b></td></td>↵
</tr>↵
<tr>↵
<td>5</td>↵
<td>[user:nikolapesic2802, 2019-06-05]</td>↵
<td><b><font color="green">30</font></b><b>:<font color="red">-14</font></b></td></td>↵
</tr>↵
</tbody>↵
</table>↵
779 successful hacks and 1077 unsuccessful hacks were made in total!↵

And finally people who were the first to solve each problem:↵
<table class='bordertable'>↵
<tbody>↵
<tr>↵
<th>Problem</th>↵
<th>Competitor</th>↵
<th>Penalty</th>↵
</tr>↵
<tr>↵
<td>A</td>↵
<td>[user:Geothermal, 2019-06-05]</td>↵
<td>0:01</td>↵
</tr>↵
<tr>↵
<td>B</td>↵
<td>[user:mango_lassi, 2019-06-05]</td>↵
<td>0:05</td>↵
</tr>↵
<tr>↵
<td>C</td>↵
<td>[user:nuip, 2019-06-05]</td>↵
<td>0:07</td>↵
</tr>↵
<tr>↵
<td>D</td>↵
<td>[user:Yushen, 2019-06-05]</td>↵
<td>0:04</td>↵
</tr>↵
<tr>↵
<td>E</td>↵
<td>[user:Sehnsucht, 2019-06-05]</td>↵
<td>0:20</td>↵
</tr>↵
<tr>↵
<td>F</td>↵
<td>[user:osaaateiasavtnl., 2019-06-05]</td>↵
<td>0:05</td>↵
</tr>↵
<tr>↵
<td>G</td>↵
<td>[user:LgndryGrandmasturbator, 2019-06-05]</td>↵
<td>0:47</td>↵
</tr>↵
</tbody>↵
</table>


**UPD:** [The editorial is out](https://codeforces.com/blog/entry/67484)

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en4 English pikmike 2019-06-06 18:51:38 76
ru4 Russian pikmike 2019-06-06 18:51:17 74
en3 English pikmike 2019-06-06 11:42:08 2680
ru3 Russian pikmike 2019-06-06 11:41:50 2650
ru2 Russian Una_Shem 2019-06-04 19:15:47 1404
en2 English Una_Shem 2019-06-04 19:11:02 1552
en1 English pikmike 2019-06-04 13:15:21 1278 Initial revision for English translation
ru1 Russian pikmike 2019-06-04 13:14:38 1397 Первая редакция (опубликовано)