#include <bits/stdc++.h>
using namespace std;
const int maxn = 1010000;
struct node {
  int x, y;
  int ord;
} ch[maxn];
bool cmp(node a, node b) { return a.x < b.x; }
bool cmp1(node a, node b) { return a.y < b.y; }
bool cmp2(node a, node b) { return a.y > b.y; }
int cnt[maxn] = {0};
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &ch[i].x, &ch[i].y);
    ch[i].ord = i + 1;
  }
  sort(ch, ch + n, cmp);
  int quan = 1, j = 0;
  for (int i = 0; i < n; i++) {
    if (ch[i].x >= 1000 * quan) {
      cnt[j++] = i;
      quan++;
    }
  }
  sort(ch, ch + cnt[0], cmp1);
  for (int i = 1; i < j; i++) {
    if (i % 2 == 0) {
      sort(ch + cnt[i - 1], ch + cnt[i], cmp1);
    } else {
      sort(ch + cnt[i - 1], ch + cnt[i], cmp2);
    }
  }
  for (int i = 0; i < n; i++) {
    printf("%d ", ch[i].ord);
  }
  return 0;
}

### Prompt

Your task is to create a CPP solution 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;
const int maxn = 1010000;
struct node {
  int x, y;
  int ord;
} ch[maxn];
bool cmp(node a, node b) { return a.x < b.x; }
bool cmp1(node a, node b) { return a.y < b.y; }
bool cmp2(node a, node b) { return a.y > b.y; }
int cnt[maxn] = {0};
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &ch[i].x, &ch[i].y);
    ch[i].ord = i + 1;
  }
  sort(ch, ch + n, cmp);
  int quan = 1, j = 0;
  for (int i = 0; i < n; i++) {
    if (ch[i].x >= 1000 * quan) {
      cnt[j++] = i;
      quan++;
    }
  }
  sort(ch, ch + cnt[0], cmp1);
  for (int i = 1; i < j; i++) {
    if (i % 2 == 0) {
      sort(ch + cnt[i - 1], ch + cnt[i], cmp1);
    } else {
      sort(ch + cnt[i - 1], ch + cnt[i], cmp2);
    }
  }
  for (int i = 0; i < n; i++) {
    printf("%d ", ch[i].ord);
  }
  return 0;
}

```