Welcome to the seventh Don Mills Open Programming Competition of the school year!

The problem writers this time are FatalEagle, Sentient, and Xyene, proofread by quantum.

This round will be rated for all participants.

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

The contest consists of 6 questions with a wide range of difficulties, and you can get partial marks for partial solutions in the form of subtasks. If you cannot solve a problem fully, we encourage you to go for these partial marks. The difficulty of a problem may be anywhere from CCC Junior to CCO level. You will have 3 hours to complete the contest. Check when the contest begins in your timezone here.

After joining the contest, you 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:

• Start from the beginning. Ties will be broken by the sum of times used to solve the problems starting from the beginning of the contest. The last submission time of your highest score will be used.
• It is strongly advised to run your code on your own computer with the sample input we provide before submitting. It's faster to find and fix mistakes at this stage rather than submitting and waiting only to find out that your solution doesn't compile.
• 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.
• Just because your program works with the sample input doesn't guarantee that it will earn full points. Read the problem statement very carefully to look for things you may have missed on the first read-through. It is not forbidden — in fact, even encouraged to make your own test cases to debug your program on.
• The test data is guaranteed to fit within the constraints given. You do not have to perform any extra checks to make sure of this fact.
• Do not just print out a hardcoded answer. There will be preliminary tests (pretests) to prevent such behavior. These pretests will generally be small enough to solve with almost any algorithm and will not contain any tricky corner cases. They are there to test for a basic understanding of a problem. The sample input will always be included as the first few pretests.
• It is guaranteed that all the problems will be solvable with C++.

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.

After the contest finishes, we'll have a optional feedback form we would like you to fill out here.

Good luck!