#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
const int inf = 1e9;
long long powm(long long a, long long p, long long m) {
  long long r = 1 % m;
  while (p) {
    if (p & 1) r = r * a % m;
    p >>= 1;
    a = a * a % m;
  }
  return r;
}
struct Node {
  int x, y, i;
};
Node ps[1000000];
bool _cmp(const Node& a, const Node& b) {
  int na = a.x / 1000, nb = b.x / 1000;
  if (na != nb) return na < nb;
  if (na % 2 == 0) return a.y < b.y || a.y == b.y && a.x < b.x;
  return a.y > b.y || a.y == b.y && a.x < b.x;
}
int main() {
  int n, x, y;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) {
    scanf("%d%d", &ps[i].x, &ps[i].y);
    ps[i].i = i + 1;
  }
  sort(ps, ps + n, _cmp);
  for (int i = 0; i < n; ++i) printf("%d ", ps[i].i);
  puts("");
  return 0;
}

### Prompt

In Cpp, your task is to solve 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 mod = 1e9 + 7;
const int inf = 1e9;
long long powm(long long a, long long p, long long m) {
  long long r = 1 % m;
  while (p) {
    if (p & 1) r = r * a % m;
    p >>= 1;
    a = a * a % m;
  }
  return r;
}
struct Node {
  int x, y, i;
};
Node ps[1000000];
bool _cmp(const Node& a, const Node& b) {
  int na = a.x / 1000, nb = b.x / 1000;
  if (na != nb) return na < nb;
  if (na % 2 == 0) return a.y < b.y || a.y == b.y && a.x < b.x;
  return a.y > b.y || a.y == b.y && a.x < b.x;
}
int main() {
  int n, x, y;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) {
    scanf("%d%d", &ps[i].x, &ps[i].y);
    ps[i].i = i + 1;
  }
  sort(ps, ps + n, _cmp);
  for (int i = 0; i < n; ++i) printf("%d ", ps[i].i);
  puts("");
  return 0;
}

```