#include <bits/stdc++.h>
using namespace std;
int read() {
  char x = getchar();
  int u = 0, fg = 0;
  while (!isdigit(x)) {
    if (x == '-') fg = 1;
    x = getchar();
  }
  while (isdigit(x)) {
    u = (u << 3) + (u << 1) + (x ^ 48);
    x = getchar();
  }
  return fg ? -u : u;
}
const int maxx = 1e6 + 10;
int n;
struct node {
  int x, y, id, posx, posy;
} a[maxx];
bool cmp(node A, node B) {
  if (A.posx == B.posx && A.posy == B.posy) {
    return A.x + A.y < B.x + B.y;
  }
  if (A.posx == B.posx) {
    if (A.posx & 1)
      return A.posy > B.posy;
    else
      return A.posy < B.posy;
  }
  return A.posx < B.posx;
}
int main() {
  n = read();
  for (register int i = (1); i <= (n); ++i) {
    a[i].x = read();
    a[i].y = read();
    a[i].id = i;
    a[i].posx = a[i].x / 1000;
    a[i].posy = a[i].y / 1000;
  }
  sort(a + 1, a + n + 1, cmp);
  for (register int i = (1); i <= (n); ++i) printf("%d ", a[i].id);
  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;
int read() {
  char x = getchar();
  int u = 0, fg = 0;
  while (!isdigit(x)) {
    if (x == '-') fg = 1;
    x = getchar();
  }
  while (isdigit(x)) {
    u = (u << 3) + (u << 1) + (x ^ 48);
    x = getchar();
  }
  return fg ? -u : u;
}
const int maxx = 1e6 + 10;
int n;
struct node {
  int x, y, id, posx, posy;
} a[maxx];
bool cmp(node A, node B) {
  if (A.posx == B.posx && A.posy == B.posy) {
    return A.x + A.y < B.x + B.y;
  }
  if (A.posx == B.posx) {
    if (A.posx & 1)
      return A.posy > B.posy;
    else
      return A.posy < B.posy;
  }
  return A.posx < B.posx;
}
int main() {
  n = read();
  for (register int i = (1); i <= (n); ++i) {
    a[i].x = read();
    a[i].y = read();
    a[i].id = i;
    a[i].posx = a[i].x / 1000;
    a[i].posy = a[i].y / 1000;
  }
  sort(a + 1, a + n + 1, cmp);
  for (register int i = (1); i <= (n); ++i) printf("%d ", a[i].id);
  return 0;
}

```