On a plane are n points (xi, yi) with integer coordinates between 0 and 106. The distance between the two points with numbers a and b is said to be the following value: <image> (the distance calculated by such formula is called Manhattan distance).

We call a hamiltonian path to be some permutation pi of numbers from 1 to n. We say that the length of this path is value <image>.

Find some hamiltonian path with a length of no more than 25 × 108. Note that you do not have to minimize the path length.

Input

The first line contains integer n (1 ≤ n ≤ 106).

The i + 1-th line contains the coordinates of the i-th point: xi and yi (0 ≤ xi, yi ≤ 106).

It is guaranteed that no two points coincide.

Output

Print the permutation of numbers pi from 1 to n — the sought Hamiltonian path. The permutation must meet the inequality <image>.

If there are multiple possible answers, print any of them.

It is guaranteed that the answer exists.

Examples

Input

5
0 7
8 10
3 4
5 0
9 12


Output

4 3 1 2 5 

Note

In the sample test the total distance is:

<image>

(|5 - 3| + |0 - 4|) + (|3 - 0| + |4 - 7|) + (|0 - 8| + |7 - 10|) + (|8 - 9| + |10 - 12|) = 2 + 4 + 3 + 3 + 8 + 3 + 1 + 2 = 26
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.StringTokenizer;
import java.io.BufferedReader;
import java.util.Comparator;
import java.util.Collections;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Artem Gilmudinov
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Reader in = new Reader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskE solver = new TaskE();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskE {
        public void solve(int testNumber, Reader in, PrintWriter out) {
            int n = in.ni();
            Point[] points = new Point[n];
            for (int i = 0; i < n; i++) {
                points[i] = new Point(in.ni(), in.ni(), i + 1);
            }
            int block = 1000;
            int mid = 1_000_000 / 2;
            ArrayList<ArrayList<Point>> blocks = new ArrayList<>();
            for (int i = 0; i <= block; i++) {
                blocks.add(new ArrayList<>());
            }
            for (Point point : points) {
                blocks.get(point.y / block).add(point);
            }
            Comparator<Point> cmp = new Comparator<Point>() {

                public int compare(Point o1, Point o2) {
                    return o1.x - o2.x;
                }
            };
            for (int i = 0; i <= block; i++) {
                Collections.sort(blocks.get(i), cmp);
            }
            ArrayList<ArrayList<Point>> bothSidesBlocks = new ArrayList<>();
            ArrayList<ArrayList<Point>> leftSideBlocks = new ArrayList<>();
            ArrayList<ArrayList<Point>> rightSideBlocks = new ArrayList<>();
            for (ArrayList<Point> b : blocks) {
                if (b.size() == 0) {
                    continue;
                }
                if (b.size() == 1) {
                    if (b.get(0).x <= mid) {
                        leftSideBlocks.add(b);
                    } else {
                        rightSideBlocks.add(b);
                    }
                } else {
                    if (b.get(0).x < mid && b.get(b.size() - 1).x > mid) {
                        bothSidesBlocks.add(b);
                    } else {
                        if (b.get(b.size() - 1).x <= mid) {
                            leftSideBlocks.add(b);
                        } else {
                            rightSideBlocks.add(b);
                        }
                    }
                }
            }
            print(bothSidesBlocks, out);
            print(leftSideBlocks, out);
            print(rightSideBlocks, out);
        }

        public void print(ArrayList<ArrayList<Point>> blocks, PrintWriter out) {
            boolean start = true;
            for (int i = 0; i < blocks.size(); i++, start = !start) {
                ArrayList<Point> b = blocks.get(i);
                if (start) {
                    for (int j = 0; j < b.size(); j++) {
                        out.print(b.get(j).id + " ");
                    }
                } else {
                    for (int j = b.size() - 1; j >= 0; j--) {
                        out.print(b.get(j).id + " ");
                    }
                }
            }
        }

        class Point extends PairInt {
            public int id;

            public Point(int x, int y, int id) {
                super(x, y);
                this.id = id;
            }

        }

    }

    static class Reader {
        private BufferedReader in;
        private StringTokenizer st = new StringTokenizer("");
        private String delim = " ";

        public Reader(InputStream in) {
            this.in = new BufferedReader(new InputStreamReader(in));
        }

        public String next() {
            if (!st.hasMoreTokens()) {
                st = new StringTokenizer(rl());
            }
            return st.nextToken(delim);
        }

        public String rl() {
            try {
                return in.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }

        public int ni() {
            return Integer.parseInt(next());
        }

    }

    static class PairInt {
        public int x;
        public int y;

        public PairInt(int x, int y) {
            this.x = x;
            this.y = y;
        }

        public String toString() {
            return x + " " + y;
        }

        public PairInt clone() {
            return new PairInt(x, y);
        }

    }
}

