#include <bits/stdc++.h>
const int N = 1000000 + 5;
const int BLOCK = 1000 + 5;
const int M = N / BLOCK + 5;
struct Point {
  int index, x, y;
  bool operator<(const Point& rhs) const { return y < rhs.y; }
};
int n;
std::vector<Point> points[M];
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    points[x / BLOCK].push_back({i + 1, x, y});
  }
  std::vector<int> answer(0);
  for (int i = 0, sign = 0; i < M; i++) {
    if (points[i].size() == 0) {
      continue;
    }
    std::sort(points[i].begin(), points[i].end());
    if (sign) {
      std::reverse(points[i].begin(), points[i].end());
    }
    for (int j = 0; j < points[i].size(); j++) {
      answer.push_back(points[i][j].index);
    }
    sign ^= 1;
  }
  for (int i = 0; i < n; i++) {
    printf("%d%s", answer[i], i == n - 1 ? "\n" : " ");
  }
  return 0;
}

### 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>
const int N = 1000000 + 5;
const int BLOCK = 1000 + 5;
const int M = N / BLOCK + 5;
struct Point {
  int index, x, y;
  bool operator<(const Point& rhs) const { return y < rhs.y; }
};
int n;
std::vector<Point> points[M];
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    points[x / BLOCK].push_back({i + 1, x, y});
  }
  std::vector<int> answer(0);
  for (int i = 0, sign = 0; i < M; i++) {
    if (points[i].size() == 0) {
      continue;
    }
    std::sort(points[i].begin(), points[i].end());
    if (sign) {
      std::reverse(points[i].begin(), points[i].end());
    }
    for (int j = 0; j < points[i].size(); j++) {
      answer.push_back(points[i][j].index);
    }
    sign ^= 1;
  }
  for (int i = 0; i < n; i++) {
    printf("%d%s", answer[i], i == n - 1 ? "\n" : " ");
  }
  return 0;
}

```