Hello Codeforces,

I'm glad to invite you to our first contest, Codeforces Round 684 (Div. 1) and Codeforces Round 684 (Div. 2) which will be held at Nov/17/2020 17:35 (Moscow time) . The problems are prepared and invented by AliShahali1382, Mehrdad_Sohrabi and Mohammad.H915. The round is rated for both divisions. You will be given 5 problems and 2:15 hours to solve them.

Firstly I'd like to thank isaf27 for coordinating and reviewing the round, as well as helping with many different things.

Finally, thanks to MikeMirzayanov for very nice and convenient Codeforces and Polygon platforms.

I wish you all will find the problems interesting, thank you for participating, and good luck!