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.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Comparator;
import java.util.StringTokenizer;
import java.util.Arrays;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Hieu Le
 */
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);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        private static final int MAX = (int) 1e6;
        private static final int WIDTH = 1000;
        private static final int CNT = MAX / WIDTH;

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            Point[] p = new Point[n];
            for (int i = 0; i < n; i++) {
                p[i] = new Point(in.nextInt(), in.nextInt(), i + 1);
            }
            Arrays.sort(p, new XComparator());
            int cur = 0;
            for (int i = 1; i <= CNT; i++) {
                if (cur == n) break;
                int begin = cur;
                while (cur < n && p[cur].x <= i * WIDTH) cur++;
                Arrays.sort(p, begin, cur);
                if ((i & 1) != 0) {
                    for (int j = begin; j < cur; j++) out.print(p[j].index + " ");
                } else {
                    for (int j = cur - 1; j >= begin; j--) out.print(p[j].index + " ");
                }
            }
        }

        class XComparator implements Comparator<Point> {
            public int compare(Point o1, Point o2) {
                return o1.x - o2.x;
            }

        }

        class Point implements Comparable<Point> {
            int x;
            int y;
            int index;

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

            public int compareTo(Point o) {
                return y - o.y;
            }

        }

    }

    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());
        }

    }
}

