#include <bits/stdc++.h>
using namespace std;
void print(int* t, int n) {
  for (int i = 0; i < n; i++) {
    printf("%d ", *(t + i) + 1);
  }
  printf("\n");
}
int n, x[1000001], y[1000001], j[1000001];
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &x[i], &y[i]);
    j[i] = i;
  }
  sort(j, j + n, [](int a, int b) {
    if (x[a] / 1000 != x[b] / 1000) return (x[a] < x[b]);
    if (x[a] / 1000 % 2) return (y[a] < y[b]);
    return (y[b] < y[a]);
  });
  print(j, n);
  return (0);
}

### Prompt

Develop a solution in cpp to the problem described below:

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;
void print(int* t, int n) {
  for (int i = 0; i < n; i++) {
    printf("%d ", *(t + i) + 1);
  }
  printf("\n");
}
int n, x[1000001], y[1000001], j[1000001];
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &x[i], &y[i]);
    j[i] = i;
  }
  sort(j, j + n, [](int a, int b) {
    if (x[a] / 1000 != x[b] / 1000) return (x[a] < x[b]);
    if (x[a] / 1000 % 2) return (y[a] < y[b]);
    return (y[b] < y[a]);
  });
  print(j, n);
  return (0);
}

```