text: #include<iostream>
  #include<vector>
  #include<bits/stdc++.h>
  using namespace std;
  int main()
  {
      int vertex,edge,source,destination;
      cin>>vertex>>edge;
      vector <int> vec[vertex];
  
      while(edge--)
      {
          cin>>source>>destination;
          vec[source].push_back(destination);
      }
  //    cout<<vec.size()<<endl;
      for(int i=0; i<vertex; i++)
      {
          int s=vec[i].size();
          cout<<"Vertex of "<<i<<": ";
          for(int j=0; j<s; j++)
          {
              cout<<vec[i][j]<<" ";
          }
          cout<<endl;
      }
      return 0;
  }
  