content: package game_meter;
  
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.util.*;
  
  public class GameMeter {
      /**
       * @param x1, y1, x2, y2 Координаты точек
       * @return Расстояние между двумя точками
       * */
      private static double distance(int x1, int y1, int x2, int y2) {
          return Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1 - y2, 2));
      }
  
      public static void main(String[] args) throws IOException {
          Scanner sc = new Scanner(new FileReader("input.txt"));
          ArrayList<String[]> coordinates = new ArrayList<>();
          Set<Double> result = new TreeSet<>();
  
          while (sc.hasNextLine()) {
              String[] line = sc.nextLine().split(" ");
              if (line.length == 2) {
                  coordinates.add(line);
              }
          }
  
          for (int i = 0; i < coordinates.size(); i++) {
              for (int j = 0; j < coordinates.size(); j++) {
                  if (i != j) {
                      result.add(distance(Integer.parseInt(coordinates.get(i)[0]),
                              Integer.parseInt(coordinates.get(i)[1]),
                              Integer.parseInt(coordinates.get(j)[0]), Integer.parseInt(coordinates.get(j)[1])));
                  }
              }
          }
  
          PrintWriter out = new PrintWriter(System.out);
          out.println(result.size());
          for (double number: result) {
              out.println(number);
          }
          out.flush();
      }
  }
  