You are given an integer n and an undirected graph with n nodes labeled from 0 to n - 1 and a 2D array edges, where edges[i] = [u_i, v_i] indicates an edge between nodes u_i and v_i.

You are also given a string label of length n, where label[i] is the character associated with node i.

You may start at any node and move to any adjacent node, visiting each node at most once.

Return the maximum possible length of a palindrome that can be formed by visiting a set of unique nodes along a valid path.

Example 1:

Input: n = 3, edges = [[0,1],[1,2]], label = "aba"

Output: 3

Explanation:

The longest palindromic path is from node 0 to node 2 via node 1, following the path 0 → 1 → 2 forming string "aba".
This is a valid palindrome of length 3.

Example 2:

Input: n = 3, edges = [[0,1],[0,2]], label = "abc"

Output: 1

Explanation:

No path with more than one node forms a palindrome.
The best option is any single node, giving a palindrome of length 1.

Example 3:

Input: n = 4, edges = [[0,2],[0,3],[3,1]], label = "bbac"

Output: 3

Explanation:

The longest palindromic path is from node 0 to node 1, following the path 0 → 3 → 1, forming string "bcb".
This is a valid palindrome of length 3.

Constraints:

1 <= n <= 14
n - 1 <= edges.length <= n * (n - 1) / 2
edges[i] == [u_i, v_i]
0 <= u_i, v_i <= n - 1
u_i != v_i
label.length == n
label consists of lowercase English letters.
There are no duplicate edges.