문제<\/h2>
In a small town called Kocourkov, surrounded by hills and woods, a strange problem has appeared. The town, known for its cozy pubs and friendly people, had always been peaceful – until a problem with mice showed up.<\/p>
But these weren’t just any mice. They were smart, quick and seemed to be everywhere at the same time. They had taken over the town’s favorite pubs, running through the rafters, nibbling on crumb, and causing a lot of trouble.<\/p>
In Kocourkov, there are $N<\/mi><\/mrow>N<\/math><\/span><\/span> N<\/span><\/span><\/span><\/span> places and exactly N<\/mi>-<\/mo>1<\/mn><\/mrow>N - 1<\/math><\/span><\/span> N<\/span> <\/span> -<\/span> <\/span><\/span> <\/span> 1<\/span><\/span><\/span><\/span> roads and it is possible to reach any place from any other place in Kocourkov via the roads. Each road connects a pair of places.<\/p> The town council held an emergency meeting in the largest pub U Nacpané Myši. They noticed that the mice are running across the city in a very particular pattern. Each mouse has exactly two lairs scattered across the city and runs only between its two lairs. Each lair is located in one of the places. It has also been observed that the mice are vulnerable about halfway through their usual path. Formally, if mouse’s lairs are in places A<\/mi><\/mrow>A<\/math><\/span><\/span> A<\/span><\/span><\/span><\/span> and B<\/mi><\/mrow>B<\/math><\/span><\/span> B<\/span><\/span><\/span><\/span> then the mouse is vulnerable at place C<\/mi><\/mrow>C<\/math><\/span><\/span>$

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