#include <bits/stdc++.h>
using namespace std;
vector<pair<int, int> > arr;
vector<int> buck[1005];
int cmp(int a, int b) { return arr[a].second < arr[b].second; }
int main() {
  int n;
  scanf("%d", &n);
  int x, y;
  int minim = 1000000, maxim = 1;
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &x, &y);
    arr.push_back(make_pair(x, y));
    minim = min(minim, x);
    maxim = max(maxim, x);
  }
  int size = (int)sqrt((double)maxim - minim);
  if (size == 0) size = (int)1e6;
  for (int i = 0; i < n; i++) {
    buck[(arr[i].first - minim) / size].push_back(i);
  }
  bool op = false;
  for (int i = 0; i <= (maxim - minim) / size; i++) {
    if (buck[i].size() == 0) continue;
    sort(buck[i].begin(), buck[i].end(), cmp);
    for (int j = 0; j < (int)buck[i].size(); j++) {
      if (op)
        printf(" ");
      else
        op = true;
      printf("%d", buck[i][j] + 1);
    }
  }
  printf("\n");
}

### Prompt

In cpp, your task is to solve 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;
vector<pair<int, int> > arr;
vector<int> buck[1005];
int cmp(int a, int b) { return arr[a].second < arr[b].second; }
int main() {
  int n;
  scanf("%d", &n);
  int x, y;
  int minim = 1000000, maxim = 1;
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &x, &y);
    arr.push_back(make_pair(x, y));
    minim = min(minim, x);
    maxim = max(maxim, x);
  }
  int size = (int)sqrt((double)maxim - minim);
  if (size == 0) size = (int)1e6;
  for (int i = 0; i < n; i++) {
    buck[(arr[i].first - minim) / size].push_back(i);
  }
  bool op = false;
  for (int i = 0; i <= (maxim - minim) / size; i++) {
    if (buck[i].size() == 0) continue;
    sort(buck[i].begin(), buck[i].end(), cmp);
    for (int j = 0; j < (int)buck[i].size(); j++) {
      if (op)
        printf(" ");
      else
        op = true;
      printf("%d", buck[i][j] + 1);
    }
  }
  printf("\n");
}

```