Problem Statement  
A vertex cactus is a connected undirected graph such that each vertex belongs to at most one simple cycle. A simple cycle is a cycle that doesn't pass through any vertex more than once. For example, the graph pictured below is a vertex cactus:
You are given an int n, the number of vertices in a graph G. The vertices are numbered from 1 to n. The edges in G are given in the String[] edges. Concatenate the elements of edges to get a commaseparated list of integer pairs. The integers in each pair are separated by a space. The pair "i j" (quotes for clarity) means that there is an edge between vertices i and j. Return the number of connected components of G that are vertex cacti.  
Definition  
 
Notes  
  A connected component of a graph G is a set of vertices such that each pair of vertices in the set is connected by a path, and no vertex outside the set is connected to any vertex within the set.  
Constraints  
  n will be between 1 and 200, inclusive.  
  edges will contain between 0 and 50 elements, inclusive.  
  Each element of edges will contain between 1 and 50 characters, inclusive.  
  When concatenated, edges will contain a comma separated list of integer pairs.  
  The integers within each pair will be separated by a space.  
  The integers within each pair will be distinct.  
  Each integer will be between 1 and n, inclusive, with no leading zeroes.  
  Every pair of vertices will be connected by at most one edge.  
Examples  
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