#include <bits/stdc++.h>
using namespace std;
int n;
struct Node {
  int x, y;
  int ix, iy;
  int id;
} node[1001000];
bool cmp(Node a, Node b) {
  if (a.ix != b.ix) return a.ix < b.ix;
  if (a.iy != b.iy) {
    if (a.ix & 1) {
      return a.iy > b.iy;
    }
    return a.iy < b.iy;
  }
  if (a.ix & 1) return a.y > b.y;
  return a.y < b.y;
}
int main() {
  while (~scanf("%d", &n)) {
    for (int i = 1; i <= n; i++) {
      scanf("%d%d", &node[i].x, &node[i].y);
      node[i].id = i;
      node[i].ix = min(node[i].x / 1000, 1000);
      node[i].iy = min(node[i].y / 1000, 1000);
    }
    sort(node + 1, node + n + 1, cmp);
    for (int i = 1; i <= n; i++) {
      printf("%d%c", node[i].id, (i == n) ? '\n' : ' ');
    }
  }
  return 0;
}

### Prompt

Please create a solution in cpp to the following problem:

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

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int n;
struct Node {
  int x, y;
  int ix, iy;
  int id;
} node[1001000];
bool cmp(Node a, Node b) {
  if (a.ix != b.ix) return a.ix < b.ix;
  if (a.iy != b.iy) {
    if (a.ix & 1) {
      return a.iy > b.iy;
    }
    return a.iy < b.iy;
  }
  if (a.ix & 1) return a.y > b.y;
  return a.y < b.y;
}
int main() {
  while (~scanf("%d", &n)) {
    for (int i = 1; i <= n; i++) {
      scanf("%d%d", &node[i].x, &node[i].y);
      node[i].id = i;
      node[i].ix = min(node[i].x / 1000, 1000);
      node[i].iy = min(node[i].y / 1000, 1000);
    }
    sort(node + 1, node + n + 1, cmp);
    for (int i = 1; i <= n; i++) {
      printf("%d%c", node[i].id, (i == n) ? '\n' : ' ');
    }
  }
  return 0;
}

```