#include <bits/stdc++.h>
using namespace std;
const int DEBUG = 0;
namespace defs {
int read() {
  int aa, bb = 1, ch;
  while (ch = getchar(), (ch < '0' || ch > '9') && ch != '-')
    ;
  ch == '-' ? aa = 0, bb = -1 : aa = ch - '0';
  while (ch = getchar(), ch >= '0' && ch <= '9') aa = aa * 10 + ch - '0';
  return aa * bb;
}
const unsigned int rand_x = 1401010315;
const unsigned int rand_y = 1000000019;
unsigned int rand_cur;
unsigned int rand_int() { return rand_cur = rand_cur * rand_x + rand_y; }
const int inf = 1071026353;
const int mod = 1000000007;
const int modx = 998244353;
const int maxn = 1000010;
}  // namespace defs
namespace lightningwork {
using namespace defs;
struct P {
  int x, y, id;
} p[maxn];
bool cmp(const P& a, const P& b) {
  if (a.x / 1000 == b.x / 1000) {
    if ((a.x / 1000) % 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);
  }
  return a.x < b.x;
}
void work() {
  int n = read();
  for (int i = 1; i <= n; ++i) {
    p[i].x = read();
    p[i].y = read();
    p[i].id = i;
  }
  sort(p + 1, p + n + 1, cmp);
  for (int i = 1; i <= n; ++i) {
    printf("%d ", p[i].id);
  }
}
}  // namespace lightningwork
int main() {
  if (0)
    freopen(
        "work"
        ".in",
        "r", stdin),
        freopen(
            "work"
            ".out",
            "w", stdout);
  lightningwork::work();
  if (0) fclose(stdin), fclose(stdout);
  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;
const int DEBUG = 0;
namespace defs {
int read() {
  int aa, bb = 1, ch;
  while (ch = getchar(), (ch < '0' || ch > '9') && ch != '-')
    ;
  ch == '-' ? aa = 0, bb = -1 : aa = ch - '0';
  while (ch = getchar(), ch >= '0' && ch <= '9') aa = aa * 10 + ch - '0';
  return aa * bb;
}
const unsigned int rand_x = 1401010315;
const unsigned int rand_y = 1000000019;
unsigned int rand_cur;
unsigned int rand_int() { return rand_cur = rand_cur * rand_x + rand_y; }
const int inf = 1071026353;
const int mod = 1000000007;
const int modx = 998244353;
const int maxn = 1000010;
}  // namespace defs
namespace lightningwork {
using namespace defs;
struct P {
  int x, y, id;
} p[maxn];
bool cmp(const P& a, const P& b) {
  if (a.x / 1000 == b.x / 1000) {
    if ((a.x / 1000) % 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);
  }
  return a.x < b.x;
}
void work() {
  int n = read();
  for (int i = 1; i <= n; ++i) {
    p[i].x = read();
    p[i].y = read();
    p[i].id = i;
  }
  sort(p + 1, p + n + 1, cmp);
  for (int i = 1; i <= n; ++i) {
    printf("%d ", p[i].id);
  }
}
}  // namespace lightningwork
int main() {
  if (0)
    freopen(
        "work"
        ".in",
        "r", stdin),
        freopen(
            "work"
            ".out",
            "w", stdout);
  lightningwork::work();
  if (0) fclose(stdin), fclose(stdout);
  return 0;
}

```