Problem B
Balanced Tree Path
You are given a tree where each node is annotated with a character from ()[]{}. A path is a sequence of one or more nodes where no node is repeated and every pair of adjacent nodes is connected with an edge. A path is balanced if the characters at each node, when concatenated, form a balanced string. A string is balanced if it satisfies the following definition:

An empty string is balanced.

If $s$ is a balanced string, then ($s$), [$s$], and {$s$} are balanced strings.

if $a$ and $b$ are balanced strings, then $ab$ ($a$ concatenated with $b$) is a balanced string.
Compute the number of balanced paths over the entire tree.
Input
The first line of input contains a single integer $n$ ($2 \le n \le 5 \cdot 10^3$).
The next line contains a string of $n$ characters, where each character is one of ()[]{}.
Each of the next $n1$ lines contains two integers, $u$ and $v$ ($1 \le u < v \le n$), indicating that nodes $u$ and $v$ are connected with an edge. It is guaranteed the graph is a tree.
Output
Output a single integer, which is the number of balanced paths over the entire tree.
Sample Input 1  Sample Output 1 

4 ()() 1 2 2 3 3 4 
4 
Sample Input 2  Sample Output 2 

4 [[]] 1 2 2 3 3 4 
2 
Sample Input 3  Sample Output 3 

6 ([]{}) 1 2 2 3 3 4 4 5 5 6 
4 