class Solution {
public:
    int makeConnected(int n, vector<vector<int>>& connections) {
        int wiresAvailaible = connections.size();
        vector<int> visited(n,0);
        vector<vector<int>> edges(n);
        int maxNode=0;
        for(auto connection:connections) {
            int from = connection[0];
            int to = connection[1];
            edges[from].push_back(to);
           //edges[to].push_back(from);
            maxNode = max(maxNode,from);
            maxNode = max(maxNode,to);

        }

        priority_queue<pair<int,pair<int,int>>,vector<pair<int,pair<int,int>>>,greater<pair<int,pair<int,int>>>> pq;


        pq.push({1,{edges[0][0],-1}});// weight , node, parent
        int wiresUsed=0;
        while(!pq.empty()) {
            auto temp = pq.top();
            pq.pop();

            int node = temp.second.first;
              if(visited[node]) continue;
            visited[node]=1;
            int parent = temp.second.second;
            wiresUsed+=1;
            for(auto  n:edges[node]) {
                if(visited[n]==0) {
                    pq.push({1,{n,node}});
                   // visited[n]=1;
                }
            }
        }

       int extraWires = wiresAvailaible-wiresUsed;
       int nodesLeftOut =n-(maxNode+1);


       int renovationsRequired = nodesLeftOut;
       if (extraWires>=renovationsRequired) return nodesLeftOut;
       return -1;

    }
};