Hello, everyone! [Codeforces Round #631](https://mirror.codeforces.com/contests/1329,1330) will be held at [contest_time:1329].↵
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The problems are almost from me([user:dreamoon_love_AA,2020-04-01]), except one problem of which the idea is from [user:drazil,2020-04-01] and developed by me. Also we want to thank [user:300iq,2020-04-01] for helping me prepare the round, [user:isaf27,2020-04-01], [user:tmt514,2020-04-01], [user:rowdark,2020-04-01], [user:yp155136,2020-04-01], [user:wangyenjen,2020-04-01], [user:n_dao107,2020-04-01] and [user:zj713300,2020-04-01] for testing this round, and MikeMirzayanov for Codeforces and Polygon.↵
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This is my third time organizing a problemset for a Codeforces round (my previous rounds: [Codeforces Round #2792](https://mirror.codeforces.com/contests/515,516), [Codeforces Round #320](https://mirror.codeforces.com/contests/578,579)).↵
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Good luck and have fun!
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The problems are almost from me([user:dreamoon_love_AA,2020-04-01]), except one problem of which the idea is from [user:drazil,2020-04-01] and developed by me. Also we want to thank [user:300iq,2020-04-01] for helping me prepare the round, [user:isaf27,2020-04-01], [user:tmt514,2020-04-01], [user:rowdark,2020-04-01], [user:yp155136,2020-04-01], [user:wangyenjen,2020-04-01], [user:n_dao107,2020-04-01] and [user:zj713300,2020-04-01] for testing this round, and MikeMirzayanov for Codeforces and Polygon.↵
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This is my third time organizing a problemset for a Codeforces round (my previous rounds: [Codeforces Round #2
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Good luck and have fun!