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
//package Codeforces;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.*;
/**
 *
 * @author Muhammad
 */
public class E_577 {
    
    static StringTokenizer st;
    static BufferedReader in;
    static PrintWriter pw;
    
    public static void main(String[] args) throws IOException{
        
        in = new BufferedReader(new InputStreamReader(System.in));
        pw = new PrintWriter(new OutputStreamWriter(System.out));;
        st = new StringTokenizer("");
        
        int n = nextInt();
        Point1 [] a = new Point1[n+1];
        
        int x = 0, y = 0;
        for(int i = 1; i <= n; i++){
            x = nextInt();
            y = nextInt();
            a[i] = new Point1(x, y, i);
        }
        Arrays.sort(a, 1, n+1);
        
        for(int i = 1; i <= n; i++){
            pw.print(a[i].id+" ");
        }
        pw.flush();
    }

    private static int nextInt() throws IOException{
        return Integer.parseInt(next());
    }

    private static String next() throws IOException{
        while(!st.hasMoreElements() || st == null){
            st = new StringTokenizer(in.readLine());
        }
        return st.nextToken();
    }
}


class Point1 implements Comparable<Point1>{
    int x; int y; int id;
    public Point1(int x, int y,int id) {
       this.x = x; this.y = y; this.id = id;
    }

    @Override
    public int compareTo(Point1 o) {
        if((this.x/1000)!=(o.x/1000)){
                return Integer.compare(this.x,o.x);
            }
            else{
                if((this.x/1000)%2==0){//even
                    return  -Integer.compare(this.y,o.y);
                }else{
                    return Integer.compare(this.y,o.y);
                }
            }
    }
}