Mirko chose a Christmas tree for the upcoming holidays and decided to decorate it
with Christmas lights. Christmas lights contain \(N\) LED lights that are connected
via (\(N - 1\)) conductive wires such that all of the lights are connected. Additionally,
we know the color of each Christmas light.
After he decorated the tree, Mirko proudly stared at his masterpiece. After a while,
he started noticing different patterns. Among those patterns, he was particularly
amazed by \(so-ca\)lled palindromic segments. Palindromic segment is a segment of
Christmas lights on the path between two fixed lights, \(u\) and \(v\), such that the array of colors on a path
from \(u\) to \(v\) is exactly the same as the array of colors on the path from \(v\) to \(u\). Determine the length of
the longest palindromic segment expressed in the number of lights on that segment.

Subtask
Score
Constraints
1
17
\(N \le 3000\)
2
25
Light \(i\) is directly connected with light \(i + 1\) (\(1 \le i < N\)).
3
31
At most 100 lights are directly connected with exactly one other light.
4
37
No additional constraints.

The first line contains an integer \(N\) (\(1 \le N \le 50\,000\)) from the task description.
The next line contains an array of \(N\) lowercase letters from the English alphabet where the \(i-th\) letter
represents the color of the \(i-th\) Christmas light.
Each of the next (\(N - 1\)) lines contains two integers \(A\) and \(B\) (\(1 \le A\), \(B \le N\), A̸ = \(B\)), which denote that
lights \(A\) and \(B\) are directly connected by a conducting wire.

The first line of output should contain the length of the longest palindromic segment.

생성자가 기록되지 않았습니다.

출처 COCI 2019/2020 Contest 3