#include <bits/stdc++.h>
using namespace std;
const int N = 1000005;
int x[N], y[N], ord[N];
int sq = 0;
bool cmp(int a, int b) {
  int ba = x[a] / sq;
  int bb = x[b] / sq;
  if (ba == bb) {
    if (ba & 1) {
      return y[a] < y[b];
    } else {
      return y[a] > y[b];
    }
  } else {
    return ba < bb;
  }
}
int main() {
  int n;
  scanf("%d", &n);
  int ma = -1;
  int mi = 1e9;
  for (int i = 0; i < n; i++) {
    scanf("%d %d", x + i, y + i);
    mi = min(mi, x[i]);
    ma = max(ma, x[i]);
    ord[i] = i;
  }
  sq = sqrt(ma - mi) + 1;
  sort(ord, ord + n, cmp);
  int dist = 0;
  for (int i = 0; i < n; i++) {
    if (i > 0)
      dist += abs(x[ord[i]] - x[ord[i - 1]]) + abs(y[ord[i]] - y[ord[i - 1]]);
    printf("%d ", ord[i] + 1);
  }
  printf("\n");
}

### 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 N = 1000005;
int x[N], y[N], ord[N];
int sq = 0;
bool cmp(int a, int b) {
  int ba = x[a] / sq;
  int bb = x[b] / sq;
  if (ba == bb) {
    if (ba & 1) {
      return y[a] < y[b];
    } else {
      return y[a] > y[b];
    }
  } else {
    return ba < bb;
  }
}
int main() {
  int n;
  scanf("%d", &n);
  int ma = -1;
  int mi = 1e9;
  for (int i = 0; i < n; i++) {
    scanf("%d %d", x + i, y + i);
    mi = min(mi, x[i]);
    ma = max(ma, x[i]);
    ord[i] = i;
  }
  sq = sqrt(ma - mi) + 1;
  sort(ord, ord + n, cmp);
  int dist = 0;
  for (int i = 0; i < n; i++) {
    if (i > 0)
      dist += abs(x[ord[i]] - x[ord[i - 1]]) + abs(y[ord[i]] - y[ord[i - 1]]);
    printf("%d ", ord[i] + 1);
  }
  printf("\n");
}

```