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
#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 5;
struct Point {
  int x, y, id;
  void read(int i) {
    scanf("%d%d", &x, &y);
    x /= 1000;
    id = i;
  }
} a[maxn];
bool cmp(const Point &a, const Point &b) {
  return a.x < b.x || a.x == b.x && (a.x & 1 ? a.y < b.y : a.y > b.y);
}
int main(void) {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) a[i].read(i);
  sort(a + 1, a + n + 1, cmp);
  for (int i = 1; i <= n; i++) printf("%d%c", a[i].id, i == n ? '\n' : ' ');
  return 0;
}
