#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 10;
int n, block;
struct node {
  int l, r, id, b;
} que[MAXN];
int read() {
  int sum = 0, fh = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') fh = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    sum = (sum << 3) + (sum << 1) + (ch ^ 48);
    ch = getchar();
  }
  return sum * fh;
}
bool cmp(const node &fir, const node &sec) {
  if (fir.b != sec.b) return fir.b < sec.b;
  if (fir.b & 1) return fir.r < sec.r;
  return fir.r > sec.r;
}
int main() {
  n = read();
  block = 1000;
  for (int i = 1; i <= n; i++) {
    que[i].l = read();
    que[i].r = read();
    que[i].id = i;
    que[i].b = (que[i].l - 1) / block + 1;
  }
  sort(que + 1, que + n + 1, cmp);
  for (int i = 1; i <= n; i++) cout << que[i].id << " ";
  cout << "\n";
  return 0;
}

### Prompt

Please provide a CPP coded solution to the problem described below:

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 MAXN = 1e6 + 10;
int n, block;
struct node {
  int l, r, id, b;
} que[MAXN];
int read() {
  int sum = 0, fh = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') fh = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    sum = (sum << 3) + (sum << 1) + (ch ^ 48);
    ch = getchar();
  }
  return sum * fh;
}
bool cmp(const node &fir, const node &sec) {
  if (fir.b != sec.b) return fir.b < sec.b;
  if (fir.b & 1) return fir.r < sec.r;
  return fir.r > sec.r;
}
int main() {
  n = read();
  block = 1000;
  for (int i = 1; i <= n; i++) {
    que[i].l = read();
    que[i].r = read();
    que[i].id = i;
    que[i].b = (que[i].l - 1) / block + 1;
  }
  sort(que + 1, que + n + 1, cmp);
  for (int i = 1; i <= n; i++) cout << que[i].id << " ";
  cout << "\n";
  return 0;
}

```