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

public class FastM {
    public static void main(String[] args) throws IOException{
        // input
        FileWriter fw = new FileWriter("visualPoints.txt", false);
        BufferedWriter write = new BufferedWriter(fw);
        int n = StdIn.readInt();
        Point[] points = new Point[n];
        for(int i = 0; i < n; i++) {		//Add points
            points[i] = new Point(StdIn.readInt(), StdIn.readInt());
        }

        // main list
        ArrayList<ArrayList<Point>> pl = new ArrayList<ArrayList<Point>>();

        // check everything
        for(int a = 0; a < n; a++) {
            Point[] temp = Arrays.copyOf(points, points.length);

            Arrays.sort(temp, temp[a].BY_SLOPE_ORDER);
            double curSlope = temp[0].getSlope(temp[1]);

            ArrayList<Point> seg = new ArrayList<>();
            for(int b = 1; b < n; b++) {
                // first iteration only
                if(seg.isEmpty()) {
                    seg.add(temp[b]);
                    curSlope = temp[0].getSlope(temp[b]);
                }
                // matching slope
                else if(curSlope == temp[0].getSlope(temp[b])) {
                    seg.add(temp[b]);
                    if(b == n - 1 && seg.size() >= 3) {
                        seg.add(temp[0]);
                        pl.add(seg);
                        seg = new ArrayList<>();
                    }
                }
                // nonmatching slope
                else{
                    if(seg.size() >= 3) {
                        seg.add(temp[0]);
                        pl.add(seg);
                        seg = new ArrayList<>();
                    }
                    seg.clear();
                    seg.add(temp[b]);
                    curSlope = temp[0].getSlope(temp[b]);
                }
            }
        }
        // sort
        for(ArrayList<Point> col : pl) Collections.sort(col);
        // remove dupes
        Set<ArrayList<Point>> ff = new HashSet<>();
        ff.addAll(pl);
        pl.clear();
        pl.addAll(ff);
        // print
        for (ArrayList<Point> elem : pl) {
            StdOut.print(elem.size() + ":");
            for (int i = 0; i < elem.size() - 1; i++) {
                StdOut.print(elem.get(i));
                StdOut.print(" -> ");
            }
            StdOut.println(elem.get(elem.size() - 1));
        }
    }
}