#include <bits/stdc++.h>
using namespace std;
const int MaxN = int(1e6) + 123;
const int Mod = int(1e9) + 7;
int n, x[MaxN], y[MaxN], magic = 2000;
vector<int> v[2222], ans;
bool cmp(int i, int j) { return y[i] < y[j]; }
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> x[i] >> y[i];
    v[x[i] / magic].push_back(i);
  }
  for (int i = 0; i <= 500; i++) sort(v[i].begin(), v[i].end(), cmp);
  int c = 0;
  for (int i = 0; i <= 500; i++) {
    if (!v[i].empty()) {
      if (c % 2 == 0)
        for (int j = 0; j < v[i].size(); j++) ans.push_back(v[i][j]);
      else
        for (int j = v[i].size() - 1; j >= 0; j--) ans.push_back(v[i][j]);
    }
  }
  for (int i = 0; i < ans.size(); i++) cout << ans[i] << " ";
  return 0;
}

### Prompt

Generate 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 = int(1e6) + 123;
const int Mod = int(1e9) + 7;
int n, x[MaxN], y[MaxN], magic = 2000;
vector<int> v[2222], ans;
bool cmp(int i, int j) { return y[i] < y[j]; }
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> x[i] >> y[i];
    v[x[i] / magic].push_back(i);
  }
  for (int i = 0; i <= 500; i++) sort(v[i].begin(), v[i].end(), cmp);
  int c = 0;
  for (int i = 0; i <= 500; i++) {
    if (!v[i].empty()) {
      if (c % 2 == 0)
        for (int j = 0; j < v[i].size(); j++) ans.push_back(v[i][j]);
      else
        for (int j = v[i].size() - 1; j >= 0; j--) ans.push_back(v[i][j]);
    }
  }
  for (int i = 0; i < ans.size(); i++) cout << ans[i] << " ";
  return 0;
}

```