#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void read(T& num) {
  bool start = false, neg = false;
  char c;
  num = 0;
  while ((c = getchar()) != EOF) {
    if (c == '-')
      start = neg = true;
    else if (c >= '0' && c <= '9') {
      start = true;
      num = num * 10 + c - '0';
    } else if (start)
      break;
  }
  if (neg) num = -num;
}
struct node {
  int x, y, ps, id;
};
const int BASE = 1000;
const int maxn = (int)(1e6) + 5;
node ai[maxn];
inline bool operator<(node a, node b) {
  if (a.ps != b.ps) return a.ps < b.ps;
  return a.y < b.y;
}
int main() {
  int n;
  read(n);
  for (int i = (1); i <= (n); i++) {
    read(ai[i].x);
    read(ai[i].y);
    ai[i].id = i;
    ai[i].ps = (ai[i].x - 1) / BASE + 1;
  }
  sort(ai + 1, ai + n + 1);
  for (int i = (1); i <= (n); i++) printf("%d ", ai[i].id);
  putchar('\n');
  return 0;
}

### Prompt

Your challenge is to write 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;
template <class T>
inline void read(T& num) {
  bool start = false, neg = false;
  char c;
  num = 0;
  while ((c = getchar()) != EOF) {
    if (c == '-')
      start = neg = true;
    else if (c >= '0' && c <= '9') {
      start = true;
      num = num * 10 + c - '0';
    } else if (start)
      break;
  }
  if (neg) num = -num;
}
struct node {
  int x, y, ps, id;
};
const int BASE = 1000;
const int maxn = (int)(1e6) + 5;
node ai[maxn];
inline bool operator<(node a, node b) {
  if (a.ps != b.ps) return a.ps < b.ps;
  return a.y < b.y;
}
int main() {
  int n;
  read(n);
  for (int i = (1); i <= (n); i++) {
    read(ai[i].x);
    read(ai[i].y);
    ai[i].id = i;
    ai[i].ps = (ai[i].x - 1) / BASE + 1;
  }
  sort(ai + 1, ai + n + 1);
  for (int i = (1); i <= (n); i++) printf("%d ", ai[i].id);
  putchar('\n');
  return 0;
}

```