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.util.*;
import java.io.*;
public class c {
public static void main(String[] args) throws Exception
{
    EspyScanner input = new EspyScanner(System.in);
    PrintWriter out = new PrintWriter(System.out);
    
    int n = input.nextInt();
    Point[] data = new Point[n];
    for(int i = 0; i<n; i++) data[i] = new Point(1+i, input.nextInt(), input.nextInt());
    ArrayList<Point>[] buckets = new ArrayList[1001];
    for(int i = 0; i<1001; i++) buckets[i] = new ArrayList<Point>();
    for(int i = 0; i<n; i++) buckets[data[i].x/1000].add(data[i]);
    for(int i = 0; i<1001; i++)
        if(buckets[i].size() > 0)
            Collections.sort(buckets[i]);
    for(int i = 0; i<1001; i++)
    {
        if(i%2 == 0)
        {
            for(int j = 0; j<buckets[i].size(); j++) out.print(buckets[i].get(j).i+" ");
        }
        else
        {
            for(int j = buckets[i].size() -1; j>=0; j--) out.print(buckets[i].get(j).i+" ");
        }
    }
    
    out.close();
}
static class Point implements Comparable<Point>
{
    int i, x, y;
    public Point(int ii, int xx, int yy)
    {
        i = ii; x = xx; y = yy;
    }
    @Override
    public int compareTo(Point o) {
        // TODO Auto-generated method stub
        if(y == o.y)return x - o.x; 
        return y - o.y;
    }
}
public static class EspyScanner {
    public final int BASE_SPEED = 110;
    public BufferedReader bf;
    public StringTokenizer st;

    public EspyScanner(InputStream in) throws Exception {
        bf = new BufferedReader(new InputStreamReader(in));
    }

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

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

    public String next() throws Exception {
        if (st == null || !st.hasMoreTokens()) {
            String line = bf.readLine();
            if (line == null) {
                return null;
            }
            st = new StringTokenizer(line);
            return next();
        }
        return st.nextToken();
    }
}
}