#include <bits/stdc++.h>
using namespace std;
int mod = 1e9 + 7;
long long powmod(long long a, long long b) {
  long long res = 1;
  if (a >= mod) a %= mod;
  for (; b; b >>= 1) {
    if (b & 1) res = res * a;
    if (res >= mod) res %= mod;
    a = a * a;
    if (a >= mod) a %= mod;
  }
  return res;
}
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
vector<int> ans[1005][1005];
inline void print(int a, int b) {
  for (int i = 0; i < ans[a][b].size(); i++) printf("%d ", ans[a][b][i]);
}
int main() {
  int i, j, t, n, x, y;
  scanf("%d", &n);
  for (i = 1; i <= n; i++) {
    scanf("%d%d", &x, &y);
    x = x / 1200;
    y = y / 1200;
    ans[x][y].push_back(i);
  }
  for (i = 0; i <= 1000; i++) {
    if (i & 1)
      for (j = 1000; j >= 0; j--) print(i, j);
    else
      for (j = 0; j <= 1000; j++) print(i, j);
  }
}

### Prompt

Please create a solution in Cpp 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;
int mod = 1e9 + 7;
long long powmod(long long a, long long b) {
  long long res = 1;
  if (a >= mod) a %= mod;
  for (; b; b >>= 1) {
    if (b & 1) res = res * a;
    if (res >= mod) res %= mod;
    a = a * a;
    if (a >= mod) a %= mod;
  }
  return res;
}
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
vector<int> ans[1005][1005];
inline void print(int a, int b) {
  for (int i = 0; i < ans[a][b].size(); i++) printf("%d ", ans[a][b][i]);
}
int main() {
  int i, j, t, n, x, y;
  scanf("%d", &n);
  for (i = 1; i <= n; i++) {
    scanf("%d%d", &x, &y);
    x = x / 1200;
    y = y / 1200;
    ans[x][y].push_back(i);
  }
  for (i = 0; i <= 1000; i++) {
    if (i & 1)
      for (j = 1000; j >= 0; j--) print(i, j);
    else
      for (j = 0; j <= 1000; j++) print(i, j);
  }
}

```