Hello Codeforces! We (dqa2021, Xiejiadong, Retired_xryjr233, Z18 and me) are excited to invite you to take part in Codeforces Round 664 (Div. 1) and Codeforces Round 664 (Div. 2), which will happen on Aug/12/2020 17:35 (Moscow time).

Huge thanks to:

• 300iq for coordinating our round.
• triple__a for answering my questions about contest preparation.
• duyiblue, jhdonghj112, jqdai0815 for providing and discussing ideas.
• gamegame, KonaeAkira, gtrhetr, jqdai0815, mayaohua2003, crasysky, aryanc403, RainAir, dqa2021, dingwanren, world_top_1_AD_uzi, Juanzhang, _Aaryan_, GavinZheng, taran_1407, yijan, whuang369, jhdonghj112 for testing and providing feedback.
• MikeMirzayanov for Codeforces and Polygon platforms.

There will be 5 problems in Div.1 round and 6 problems in Div.2 round. You'll be given 2 hours to solve them.

The story of this round is about that man. Instead of displaying his name, I prefer telling one of his legends (or joke):

"I have a 'friend', who makes lots of money every day, earning a billion in the blink of eyes. With a wave of his hand, OIers all over the world will follow him."

You can post your guesses in the comments.

Good luck!