#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-6;
const int INF = 0x3f3f3f3f, N = 2000005, M = 2000005, MOD = 1e9 + 7;
int sgn(double x) { return x < -eps ? -1 : (x < eps ? 0 : 1); }
int Rand(int x) { return rand() * rand() % x + 1; }
struct node {
  int x, y, bel, id;
} a[N];
int Solve() {
  int n;
  cin >> n;
  int sn = sqrt(1000000);
  for (int i = 1; i <= n; i++) {
    cin >> a[i].x >> a[i].y;
    a[i].bel = a[i].x / sn;
    a[i].id = i;
  }
  sort(a + 1, a + 1 + n, [](node a, node b) {
    if (a.bel != b.bel) return a.bel < b.bel;
    if (a.bel & 1)
      return a.y < b.y;
    else
      return a.y > b.y;
  });
  for (int i = 1; i <= n; i++) {
    cout << a[i].id;
    if (i == n)
      cout << '\n';
    else
      cout << " ";
  }
  return 0;
}
void Pre() {}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0), cout.tie(0);
  Pre();
  while (Solve())
    ;
  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;
const double eps = 1e-6;
const int INF = 0x3f3f3f3f, N = 2000005, M = 2000005, MOD = 1e9 + 7;
int sgn(double x) { return x < -eps ? -1 : (x < eps ? 0 : 1); }
int Rand(int x) { return rand() * rand() % x + 1; }
struct node {
  int x, y, bel, id;
} a[N];
int Solve() {
  int n;
  cin >> n;
  int sn = sqrt(1000000);
  for (int i = 1; i <= n; i++) {
    cin >> a[i].x >> a[i].y;
    a[i].bel = a[i].x / sn;
    a[i].id = i;
  }
  sort(a + 1, a + 1 + n, [](node a, node b) {
    if (a.bel != b.bel) return a.bel < b.bel;
    if (a.bel & 1)
      return a.y < b.y;
    else
      return a.y > b.y;
  });
  for (int i = 1; i <= n; i++) {
    cout << a[i].id;
    if (i == n)
      cout << '\n';
    else
      cout << " ";
  }
  return 0;
}
void Pre() {}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0), cout.tie(0);
  Pre();
  while (Solve())
    ;
  return 0;
}

```