EVEN-TREE

int evenForest(int t_nodes, int t_edges, vector<int> t_from, vector<int> t_to) {

        int e=t_from.size();   
        for(int i=0;i<e;i++)
        {
            adj[t_from[i]].push_back(t_to[i]);
            adj[t_to[i]].push_back(t_from[i]);
            edges[i]=make_pair(t_from[i],t_to[i]);
        }
         int ans=0;
        for(int i=0;i<e;i++)
        {
               if(bfs(edges[i].first,edges[i].second)%2==0 && bfs(edges[i].second,edges[i].first)%2==0 )
               {
                   ans++;
                   auto f=find(adj[edges[i].first].begin(),adj[edges[i].first].end(),edges[i].second);
                   
                   if(f!=adj[edges[i].first].end())
                      adj[edges[i].first].erase(f);
               }
        }

        return ans;

}