#include <bits/stdc++.h>
const int len(1000000);
int block[len + 10], leng;
struct Question {
  int l, r, pos;
  inline bool operator<(const Question &a) const {
    return (block[l] == block[a.l]) ? r < a.r : l < a.l;
  }
} A[len + 10];
long long ans[len + 10], sum;
template <class T>
void read(T &x) {
  x = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9') ch = getchar();
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
}
int n;
int main() {
  read(n);
  leng = sqrt(len);
  for (int i = 1; i <= len; i++)
    block[i] = (i % leng == 1) ? block[i - 1] + 1 : block[i - 1];
  for (int i = 1; i <= n; i++) read(A[i].l), read(A[i].r), A[i].pos = i;
  std::sort(A + 1, A + 1 + n);
  for (int i = 1; i <= n; i++) printf("%d ", A[i].pos);
  return 0;
}

### Prompt

Develop a solution in CPP 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>
const int len(1000000);
int block[len + 10], leng;
struct Question {
  int l, r, pos;
  inline bool operator<(const Question &a) const {
    return (block[l] == block[a.l]) ? r < a.r : l < a.l;
  }
} A[len + 10];
long long ans[len + 10], sum;
template <class T>
void read(T &x) {
  x = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9') ch = getchar();
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
}
int n;
int main() {
  read(n);
  leng = sqrt(len);
  for (int i = 1; i <= len; i++)
    block[i] = (i % leng == 1) ? block[i - 1] + 1 : block[i - 1];
  for (int i = 1; i <= n; i++) read(A[i].l), read(A[i].r), A[i].pos = i;
  std::sort(A + 1, A + 1 + n);
  for (int i = 1; i <= n; i++) printf("%d ", A[i].pos);
  return 0;
}

```