It is well known that wleung_bvg is always angry. To vent out his anger, he decided to create a contest.

After reading a complaint about there not being enough fun graph problems on this year's CCC, he decided to make a whole contest of them! Here are the parameters of the contest:

• Contest duration: 4 hours.
• Number of problems: 7, full feedback. Each problem will be worth 100 points, and will have subtasks that offer various amounts of partial credit.
• Rated for all participants who submit at least once.
• Scoreboard will be visible.
• No submission limit.
• Ties will be broken by the sum of times used to solve the problems starting from the beginning of the contest. The first submission time of your highest score will be used.
• Checkers for problems: Unless otherwise specified, identical. The contest will follow the standard convention of having all lines terminate in a \n character, with no trailing whitespace.

Furthermore, users are forbidden from using multiple accounts or collaborating during the entire contest duration. Any suspicious behaviour during the contest window may result in a severe penalty including, but not limited to, being placed at the bottom of the scoreboard.

Special thanks to Dormi, PlasmaVortex, Plasmatic, crackersamdjam, alextxu, and insignificant for providing feedback and testing the problems.

Before the contest date, you may wish to check out the tips and help pages.

This contest will consist of ~7~ problems, the difficulty of which may range anywhere from CCC Senior to IOI level. For this contest, all problems will have some graph theory component.

Some problems offer partial marks in the form of subtasks. If you cannot solve a problem fully, we encourage you to go for these partial marks.

You will have 4 hours to complete the contest. After the contest window begins (9:00 AM EDT of June 29th), you may begin at any time. Once you enter the contest, your personal timer will start counting down and you will be able to submit until 4 hours from when you started, or until the hard deadline (11:59 PM EDT of July 1st), whichever comes first.

After joining the contest, you can proceed to the Problems tab to begin. You can also go to Users if you wish to see the rankings.

We have listed below some advice as well as contest strategies:

• It is not guaranteed that the problems will be in order of increasing difficulty. Reading all of the statements is recommended.
• Remove all extra debugging code and/or input prompts from your code before submitting. The judge is very strict - most of the time, it requires your output to match exactly.
• Do not pause program execution at the end. The judging process is automated. You should use stdin / stdout to perform input / output, respectively.
• It is guaranteed that all the problems will be solvable with C++. All problems have a time limit of at least 1.5x the reference solution, which is written in C++ and uses this template for I/O. If you're unable to see the template, you must solve this problem.

At the end of the contest, you may comment below to appeal a judging verdict. In the case of appeals, the decision(s) of DMOJ staff is final.