Unfortunately, due to current circumstances, no one could really embark on a journey around the world. Fortunately, quantum has an idea — let's make a programming contest to simulate the experience of a world tour, all in the comfort of your home.

Four problems await you in this contest, leading you on an exciting week-long trip through the world... and even through time. Of course, you will face challenges, but they can't be that hard to overcome. No harder than doing quantum one small favour, for sure.

A few notes about this content:

• Contest duration: 1 week.
• Number of problems: 4.
• Unrated.
• Scoreboard will be public.

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

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.
• Remove all extra debugging code and/or input prompts from your code before submitting. The judge is strict — your output must match the judge output exactly.
• Do not pause program execution at the end. The judging process is automated.