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 com.sun.org.apache.bcel.internal.generic.ARRAYLENGTH;

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;


public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(in, out);
        out.close();
    }

    static class Task {

        public void solve(InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int block = 1000;
            Point[] p = new Point[n];

            for(int i = 0; i < n; i++)
                p[i] = new Point(in.nextInt(), in.nextInt(), i + 1);

            ArrayList<ArrayList<Point>> list = new ArrayList<>();
            for(int i = 0; i <= block; i++)
                list.add(new ArrayList<Point>());

            for(Point point : p) {
                list.get(point.x / block).add(point);
            }

            for(int i = 0; i <= block; i++) {
                Collections.sort(list.get(i), new Comparator<Point>() {
                    @Override
                    public int compare(Point point, Point t1) {
                        return point.y - t1.y;
                    }
                });
                if(i % 2 == 1)
                    Collections.reverse(list.get(i));
            }

            for(int i = 0; i <= block; i++) {
                for(Point point : list.get(i))
                    out.print(point.id + " ");
            }
        }

        class Point extends PairInt {

            public int id;

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

        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

        public long nextLong() {
            return Long.parseLong(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public float nextFloat() {
            return Float.parseFloat(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);
        }

    }
}