#include <bits/stdc++.h>
using namespace std;
const int inf = 1 << 28;
const int mod = (int)1e9 + 7;
const double eps = 1e-8;
const double pi = acos(-1.0);
int n, m, k;
struct node {
  int x, y, id;
  node(int xx = 0, int yy = 0, int iid = 0) : x(xx), y(yy), id(iid) {}
};
vector<node> v;
bool cmp(node a, node b) {
  int x1 = a.x / 1000;
  int x2 = b.x / 1000;
  if (x1 != x2) return x1 < x2;
  if (x1 & 1)
    return a.y < b.y;
  else
    return a.y > b.y;
}
int main() {
  while (~scanf("%d", &n)) {
    int a, b;
    for (int i = 1; i <= n; i++) {
      scanf("%d %d", &a, &b);
      v.push_back(node(a, b, i));
    }
    sort(v.begin(), v.end(), cmp);
    cout << v[0].id;
    for (int i = 1; i < v.size(); i++) {
      cout << " " << v[i].id;
    }
    cout << endl;
  }
  return 0;
}

### Prompt

Create a solution in Cpp for 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 inf = 1 << 28;
const int mod = (int)1e9 + 7;
const double eps = 1e-8;
const double pi = acos(-1.0);
int n, m, k;
struct node {
  int x, y, id;
  node(int xx = 0, int yy = 0, int iid = 0) : x(xx), y(yy), id(iid) {}
};
vector<node> v;
bool cmp(node a, node b) {
  int x1 = a.x / 1000;
  int x2 = b.x / 1000;
  if (x1 != x2) return x1 < x2;
  if (x1 & 1)
    return a.y < b.y;
  else
    return a.y > b.y;
}
int main() {
  while (~scanf("%d", &n)) {
    int a, b;
    for (int i = 1; i <= n; i++) {
      scanf("%d %d", &a, &b);
      v.push_back(node(a, b, i));
    }
    sort(v.begin(), v.end(), cmp);
    cout << v[0].id;
    for (int i = 1; i < v.size(); i++) {
      cout << " " << v[i].id;
    }
    cout << endl;
  }
  return 0;
}

```