bruce is hosting a series of weekly CCO training contests, and everyone is welcome to participate!

Whether you've been invited to the CCO or not, this is a great opportunity to sharpen your skills:

• CCO Invitees: Use these contests to stay in shape and prepare for the CCO ahead.
• Non-invitees: This is your chance to challenge and outperform the CCO invitees — show them what you’ve got!

Here are the parameters of the contest:

• Contest duration: 4 hours.
• Number of problems: 3, full feedback (you will see the results of your submissions instantly).
• Scoreboard will be hidden, until your window is over.
• Each problem will be worth 100 marks, and may have partial marks in the form of subtasks.
• Checkers for problems: standard, unless otherwise specified.
• This contest is unrated.
• It is guaranteed that all problems will be solvable with C++.

Note: Problems are not guaranteed to be ordered by difficulty