Hello! I'm happy to announce XX Open Cup: Grand Prix of Nanjing, which will be held on May 3rd, 2020.

This contest is mainly prepared by gisp_zjz and me, which has already been used in Moscow Pre-Finals Workshop 2020 Day 5 on April 29th, 2020.

As you can see on the top of the statement, this contest is also been called Legilimens+Coffee Chicken Contest. Team Coffee Chicken from Nanjing University will participate in World Finals 2020 and we wish them best luck in Moscow. Team Legilimens is from Zhejiang University, which is my team in the past 3 years. Although we didn't get advanced to World Finals 2020 and this is the end of our journey, we have experienced a lot of happy and unforgettable moments. Therefore, please allow me to express my gratefulness to my teammates Subconscious and oipotato. And may the friendship between Nanjing University and Zhejiang University last forever.

Authors of this contest come from Competitive Programming Team members from both Zhejiang University and Nanjing University, including gisp_zjz, AceSrc, zyb, Roundgod, calabash_boy, sy_chen, chenjb, Subconscious, oipotato, Sugar_fan, etc.

Testers: mayaohua2003, gtrhetr, xiaowuc1. Thank you!

Contest link: http://official.contest.yandex.ru/opencupXX/contest/18242/enter (Only visible for users with OpenCup login)

I will post the editorial after the contest. We are looking forward to your participation!

UPD: Now it is over. Please feel free to discuss solutions and this is the Editorial Sketch.