#include <bits/stdc++.h>
using namespace std;
int OK = 1;
const int INF = 0x3f3f3f3f;
const int maxn = 1001000;
struct node {
  int x, y, id;
} pt[maxn];
bool cmp(node a, node b) {
  if (a.x != b.x) return a.x < b.x;
  return a.y < b.y;
}
int arr[maxn];
int main() {
  int n;
  cin >> n;
  int tot = 0, flag = 0;
  vector<node> ans[1100];
  for (int i = 0; i < n; ++i) {
    scanf("%d%d", &pt[i].x, &pt[i].y);
    pt[i].id = i + 1;
    ans[pt[i].y / 1000].push_back(pt[i]);
  }
  for (int i = 0; i < 1005; ++i) {
    if (ans[i].empty()) continue;
    sort(ans[i].begin(), ans[i].end(), cmp);
    if (flag) reverse(ans[i].begin(), ans[i].end());
    flag ^= 1;
    for (auto jj : ans[i]) arr[tot++] = jj.id;
  }
  for (int i = 0; i < n; i++) printf("%d ", arr[i]);
  return 0;
}

### Prompt

Construct a CPP code solution to the problem outlined:

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;
int OK = 1;
const int INF = 0x3f3f3f3f;
const int maxn = 1001000;
struct node {
  int x, y, id;
} pt[maxn];
bool cmp(node a, node b) {
  if (a.x != b.x) return a.x < b.x;
  return a.y < b.y;
}
int arr[maxn];
int main() {
  int n;
  cin >> n;
  int tot = 0, flag = 0;
  vector<node> ans[1100];
  for (int i = 0; i < n; ++i) {
    scanf("%d%d", &pt[i].x, &pt[i].y);
    pt[i].id = i + 1;
    ans[pt[i].y / 1000].push_back(pt[i]);
  }
  for (int i = 0; i < 1005; ++i) {
    if (ans[i].empty()) continue;
    sort(ans[i].begin(), ans[i].end(), cmp);
    if (flag) reverse(ans[i].begin(), ans[i].end());
    flag ^= 1;
    for (auto jj : ans[i]) arr[tot++] = jj.id;
  }
  for (int i = 0; i < n; i++) printf("%d ", arr[i]);
  return 0;
}

```