Hello, Codeforces!

We are proud to invite you to participate in Atto Round 1 (Codeforces Round 1041, Div. 1 + Div. 2) which will be held on Aug/07/2025 17:35 (Moscow time).

The round will be rated for everyone. You will be given 8 problems, one of which is divided into two subtasks, and 3 hours to solve them. One of the problems will be interactive, so make sure to read the guide for interactive problems before the contest.

The score distribution will be announced later.

The problems are authored and prepared by Ali_BBN, Bahamin, _R00T, eren__, sweetweasel, and me.

We would like to thank:

• Error_Yuan for his great coordination.
• Alexdat2000 for Russian translation.
• errorgorn, StarSilk for nutella testing.
• _istil, abc864197532, yuanruiqi, LMydd0225, A_G, maomao90, AmShZ, N_z__, Keshi, zeemanz for red testing.
• arashmemar, ooscode, A_M_Namdar, radal, mohammadsam, ParsaF, IliyaEslahi for orange testing.
• AlefHeKaaf, Shahrad_Mirzaei, rewhile, Siyah, ParsaS for purple testing.
• theSkeleton, iliya_mon, Kosar, amir_AP, Ardelion, KiaRash24, hamidh100, mathtsai, Behrad. for blue testing.
• FrontMan. for cyan testing.
• MikeMirzayanov and KAN for the great platforms.
• You for participating!

Now, a few words from our sponsor!

At Atto Trading, we are a science-driven quantitative trading firm where engineers, quants, and researchers combine their efforts to engineer cutting-edge trading systems that execute in nanoseconds, powering decisions at the speed of light in the world’s most competitive market. Many of our team members started their journey on platforms like Codeforces. We are thrilled to announce our own round on Codeforces platform.

Follow the link below and complete the application form to explore career opportunities with us.

We prepared some exciting rewards for participants in this round.

• Rank 1: Apple MacBook + backpack + branded T‑shirt + sports bag
• Ranks 2-3: Apple iPad + backpack + branded T‑shirt + sports bag
• Ranks 4-5: Apple Watch + backpack + branded T‑shirt + sports bag
• Ranks 6-20: Backpack + branded T‑shirt + sports bag
• Ranks 21-100: Branded T‑shirt + sports bag

If we encounter difficulties delivering your gift, we reserve the right to reimburse its value in cryptocurrency

Good luck!