void dfsHelper(T src, unordered_map<T, bool> &visited, vector<T> &r)
{
    //marking a node visited as soon as it is pushed in
    //internal call stack
    visited[src]=true;

    //push src in the result
    r.push_back(src);

    //go to all the unvisited nodes of the current
    //node, but one by one
    for(auto x: mp[src])
    {
       //check if already visited or not
       if(!visited[x])
       {
          //push it in the stack(internal call stack is used)
          dfsHelper(x, visited, r);
       }
    }
}

int dfs(T src)
{
   //to store one of the many possible dfs traversal,
   //using any vertex as source(starting vertex)
   vector<T> r;

   //to check if a vertex isVisited
   unordered_map<T, bool> visited;

   int count=0; // to store the count of connected compo.
   for(auto p: mp)
   {
        if(!visited[p.first])
        {
            cnt++;

            //helper function
            dfsHelper(p.first, visited, r);
        }
   }

   return count;
}

// NOTE: The same result can also be achieved using BFS also.