public class Fast {
    public static void main(String[] args) {
        int n = StdIn.readInt();
        Point points[] = new Point[n];
        for (int i = 0; i < n; i++) {
            points[i] = (new Point(StdIn.readInt(), StdIn.readInt()));
        }

        Arrays.sort(points);
        //Map<Double, ArrayList<Point>> map = new HashMap<Double, ArrayList<Point>>();
        TreeMap<Double, ArrayList<Point>> sortedMap = new TreeMap<Double, ArrayList<Point>>();
        Double slope = 0.0;
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                slope = points[i].slopeTo(points[j]);
                if (!sortedMap.containsKey(slope)) {
                    sortedMap.put(slope, new ArrayList<Point>());
                    sortedMap.get(slope).add(points[i]);
                }
                if (!sortedMap.get(slope).contains(points[j]))
                    sortedMap.get(slope).add(points[j]);
            }
        }
        //sortedMap.putAll(map);
        for (ArrayList<Point> list : sortedMap.values()) {
            int count = 0;
            if (list.size() >= 4){
                count = 0;
                for (Point p : list) {
                    StdOut.print(p);
                    count++;
                    if (count < list.size())
                        StdOut.print(" -> ");
                }
                count++;
                if (count < sortedMap.size()){
                    StdOut.print("\n");
                }
            }
        }
    }
}