import java.io.*;
import java.util.*;
import java.math.*;


public class COLORS
{
  public COLORS() throws IOException
  {


     FileReader fr = new FileReader("COLORS.IN");
     BufferedReader br = new BufferedReader(fr);

     int numSets = Integer.parseInt(br.readLine());

     DataSet ds[] = new DataSet[numSets];

     // read in data sets
     for (int i = 0; i < numSets; i++)
     {
       int numColors = Integer.parseInt(br.readLine());
       RGB colorsSet[] = new RGB[numColors];


       // read in colors
       for (int k = 0; k < numColors; k++)
       {

         String args = br.readLine();
         StringTokenizer tok = new StringTokenizer(args);

         colorsSet[k] = new RGB(Integer.parseInt(tok.nextToken()), Integer.parseInt(tok.nextToken()), Integer.parseInt(tok.nextToken()));
       }

       ds[i] = new DataSet(i, colorsSet);

     }


     // output
     for (int i = 0; i < numSets; i++)
     {
       int setNumber = i + 1;
       System.out.println("Data Set " + setNumber + ":");


       RGB set[] = ds[i].colors;

       int possibleCombos = set.length * set.length - set.length;
       OneSet oneSet[] = new OneSet[possibleCombos];
       //System.out.println(possibleCombos);
       int index = 0;

       // calculate contrast
       for (int firstSet = 0; firstSet < set.length; firstSet++)
       {
         for (int secondSet = 0; secondSet < set.length; secondSet++)
         {
           if (firstSet == secondSet)
             continue;
           else
           {
             oneSet[index] = new OneSet(firstSet, secondSet,
                                        calcContrast(set[firstSet],
                 set[secondSet]));
             index++;
           }
         }
       }


       double[] array = new double[oneSet.length];

       for (int bla = 0; bla < oneSet.length; bla++)
       {
         array[bla] = oneSet[bla].contr;
       }

       java.util.Arrays.sort(array);

       //System.out.println(array.length);


      double contrast = array[array.length-1];//oneSet[0].contr;
      ArrayList output = new ArrayList();


      //System.out.println(set.length);
       for (int k = 0; k < oneSet.length; k++)
       {
         //;

         //System.out.println(oneSet[k].contr);

         if (oneSet[k].contr == contrast)
         {
           //RGB s = set[oneSet[k].row1];
           int row1 = oneSet[k].row1;
           int row2 = oneSet[k].row2;

           output.add(new Output(row1, row2));

           //System.out.println(row1 + " " + row2);

         }
       }

       ArrayList fin = new ArrayList();

       for (int d = 0; d < output.size(); d++)
       {
          for (int g = 0; g < output.size(); g++)
          {
              Output one = (Output)output.get(d);
              Output two = (Output)output.get(g);

              if (one.row1 == two.row2 && one.row2 == two.row1)
              {
                if (one.row1 < one.row2)
                  output.remove(two);
              }
          }
       }

       for (int xoxo = 0; xoxo < output.size(); xoxo++)
       {
         Output x = (Output)output.get(xoxo);
         int row1 = x.row1+1;
           int row2 = x.row2+1;

           System.out.println(row1 + " " + row2);

       }

     }


  }
  public static void main (String ar[]) throws Exception
  {
     new COLORS();


  }

  public double calcContrast(RGB set1, RGB set2)
  {
    double R_dif = set1.R - set2.R;

    double G_dif = set1.G - set2.G;

    double B_dif = set1.B - set2.B;

    double sr = Math.sqrt(R_dif*R_dif+G_dif*G_dif+B_dif*B_dif);

    //System.out.println(sr);

    return sr;
  }

  private class DataSet
  {
    public int num;
    public RGB[] colors;

    public DataSet(int num, RGB[] colors)
    {
      this.num = num;
      this.colors = colors;
    }


  }

  private class RGB
  {
    public int R;
    public int G;
    public int B;

    public RGB(int r, int g, int b)
    {
      this.R = r;
      this.G= g;
      this.B = b;

    }
  }

  private class OneSet
  {
    public int row1;
    public int row2;
    public double contr;

    public OneSet(int r1, int r2, double con)
    {
      row1 = r1;
      row2 = r2;

      contr = con;
    }


  }

  private class Output
  {
    public int row1;
    public int row2;

    public Output(int r1, int r2)
    {
      row1 = r1;
      row2=r2;
    }

  }
}