#include <bits/stdc++.h>
using namespace std;
struct point {
  int index;
  int x, y;
} pnt[1000009];
bool lowcmp(point a, point b) {
  if (a.y != b.y) return a.y < b.y;
  return a.x < b.x;
}
bool greaterCmp(point a, point b) {
  if (a.y != b.y) return a.y > b.y;
  return a.x > b.x;
}
vector<int> ans;
vector<point> lay[1009];
int main() {
  int n;
  while (scanf("%d", &n) != EOF) {
    for (int i = 0; i < n; i++) {
      scanf("%d%d", &pnt[i].x, &pnt[i].y);
      pnt[i].index = i + 1;
      lay[pnt[i].x / 1000].push_back(pnt[i]);
    }
    for (int i = 0; i < 1001; i++) {
      if (i & 1) {
        sort(lay[i].begin(), lay[i].end(), lowcmp);
      } else {
        sort(lay[i].begin(), lay[i].end(), greaterCmp);
      }
      for (auto b : lay[i]) {
        ans.push_back(b.index);
      }
    }
    for (auto i : ans) {
      printf("%d ", i);
    }
  }
  return 0;
}

### Prompt

Please formulate 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;
struct point {
  int index;
  int x, y;
} pnt[1000009];
bool lowcmp(point a, point b) {
  if (a.y != b.y) return a.y < b.y;
  return a.x < b.x;
}
bool greaterCmp(point a, point b) {
  if (a.y != b.y) return a.y > b.y;
  return a.x > b.x;
}
vector<int> ans;
vector<point> lay[1009];
int main() {
  int n;
  while (scanf("%d", &n) != EOF) {
    for (int i = 0; i < n; i++) {
      scanf("%d%d", &pnt[i].x, &pnt[i].y);
      pnt[i].index = i + 1;
      lay[pnt[i].x / 1000].push_back(pnt[i]);
    }
    for (int i = 0; i < 1001; i++) {
      if (i & 1) {
        sort(lay[i].begin(), lay[i].end(), lowcmp);
      } else {
        sort(lay[i].begin(), lay[i].end(), greaterCmp);
      }
      for (auto b : lay[i]) {
        ans.push_back(b.index);
      }
    }
    for (auto i : ans) {
      printf("%d ", i);
    }
  }
  return 0;
}

```