Hello, Codeforces!↵
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I'm glad to invite you to Round 643 which will start at [contest_time:1355]. **Please notice the unusual time.**↵
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There will be 6 problems in round, one of them will be interactive. If you are not familiar with interactive problems, you can learn about them [here](https://mirror.codeforces.com/blog/entry/45307).↵
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Round is based on Team Olympiad in Lipetsk which is being held for the fifth time. Problems were prepared by [user:fake123,2020-05-13], [user:iura,2020-05-13], [user:Masha237,2020-05-13], [user:Villen3tenmerth,2020-05-13], Inessa Shujkova (Lipetsk teams' coach) and me. I would like to thank [user:antontrygubO_o,2020-05-13] for CF round coordination and testers: [user:KAN,2020-05-13], [user:I_love_Tanya_Romanova,2020-05-13], [user:vepifanov,2020-05-13], [user:Merkurev,2020-05-13], [user:golikovnik,2020-05-13], [user:Ekler,2020-05-13] and some other people who asked me not to write about them :)↵
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Of course, I'd like to thank all Codeforces team for this beautiful platform!↵
↵
Scoring distribution will be announced later.↵
↵
Wish you good luck and high rating!↵
↵
**UPD.1** Scoring distribution: $750-750-1250-1500-2000-3000$.↵
↵
**UPD.2** Editorial is available [here](https://mirror.codeforces.com/blog/entry/77491).
↵
I'm glad to invite you to Round 643 which will start at [contest_time:1355]. **Please notice the unusual time.**↵
↵
There will be 6 problems in round, one of them will be interactive. If you are not familiar with interactive problems, you can learn about them [here](https://mirror.codeforces.com/blog/entry/45307).↵
↵
Round is based on Team Olympiad in Lipetsk which is being held for the fifth time. Problems were prepared by [user:fake123,2020-05-13], [user:iura,2020-05-13], [user:Masha237,2020-05-13], [user:Villen3tenmerth,2020-05-13], Inessa Shujkova (Lipetsk teams' coach) and me. I would like to thank [user:antontrygubO_o,2020-05-13] for CF round coordination and testers: [user:KAN,2020-05-13], [user:I_love_Tanya_Romanova,2020-05-13], [user:vepifanov,2020-05-13], [user:Merkurev,2020-05-13], [user:golikovnik,2020-05-13], [user:Ekler,2020-05-13] and some other people who asked me not to write about them :)↵
↵
Of course, I'd like to thank all Codeforces team for this beautiful platform!↵
↵
Scoring distribution will be announced later.↵
↵
Wish you good luck and high rating!↵
↵
**UPD.1** Scoring distribution: $750-750-1250-1500-2000-3000$.↵
↵
**UPD.2** Editorial is available [here](https://mirror.codeforces.com/blog/entry/77491).
