private static void Get_dMins(StringTokenizer st, BufferedReader br) throws IOException {
        potentials = new LinkedList<>();
        int x, y, phi;
        for (int i = 0; i < P; i++) {
            st = new StringTokenizer(br.readLine(), " ");
            x = Integer.parseInt(st.nextToken())-1;
            y = Integer.parseInt(st.nextToken())-1;
            phi = Integer.parseInt(st.nextToken());
            potentials.add(graph[x][y]);

            graph[x][y].d_min = 0;
            graph[x][y].phi_min = phi;
        }
        Collections.sort(potentials, new VertexComparator());

    }

private static void FillInVerticesNumbers() {
        while(!potentials.isEmpty()){
            Vertex act = potentials.pop();
            int phi = act.phi_min;
            int d = act.d_min +1;
            for(Edge e : act.edges){
               Vertex v = e.v1;
               if(v.equals(act)){
                   v = e.v2;
               }
                if(v.d_min>d){
                    v.phi_min = phi;
                    v.d_min = d;
                    potentials.add(v);
                }
            }
        }
    }