#include <bits/stdc++.h>
using namespace std;
class Point {
 public:
  int x, y, index;
  Point(int xt, int yt, int i) {
    index = i;
    x = xt;
    y = yt;
  }
  Point() { x = y = index = 0; }
};
long long dist(Point p1, Point p2) {
  long long a = p1.x - p2.x;
  long long b = p1.y - p2.y;
  if (a < 0) a = -a;
  if (b < 0) b = -b;
  return (a + b);
}
struct comparex {
  bool operator()(const Point &p1, const Point &p2) { return (p1.x < p2.x); }
};
struct comparey {
  bool operator()(const Point &p1, const Point &p2) { return (p1.y < p2.y); }
};
int main() {
  int n, c = 0;
  scanf("%d", &n);
  long long total = 0;
  vector<vector<Point> > point(1000, vector<Point>(0));
  Point p[n];
  for (int i = 0; i < n; i++) {
    int x, y;
    scanf("%d %d", &x, &y);
    if (y == 1000000)
      point[999].push_back(Point(x, y, i + 1));
    else
      point[y / 1000].push_back(Point(x, y, i + 1));
  }
  for (int i = 0; i < 1000; i++)
    sort(point[i].begin(), point[i].end(), comparex());
  for (int i = 0; i < 1000; i++) {
    if (i % 2 == 0) {
      for (int j = 0; j < point[i].size(); j++) {
        p[c] = point[i][j];
        if (c > 0) total = total + dist(p[c], p[c - 1]);
        c++;
      }
    } else {
      for (int j = point[i].size() - 1; j >= 0; j--) {
        p[c] = point[i][j];
        if (c > 0) total = total + dist(p[c], p[c - 1]);
        c++;
      }
    }
  }
  if (total > 2500000000) {
    for (int i = 0; i < 1000; i++) point[i].clear();
    for (int i = 0; i < n; i++) {
      if (p[i].x == 1000000)
        point[999].push_back(p[i]);
      else
        point[p[i].x / 1000].push_back(p[i]);
    }
    for (int i = 0; i < 1000; i++)
      sort(point[i].begin(), point[i].end(), comparey());
  }
  for (int i = 0; i < 1000; i++) {
    if (i % 2 == 0) {
      for (int j = 0; j < point[i].size(); j++)
        printf("%d ", point[i][j].index);
    } else {
      for (int j = point[i].size() - 1; j >= 0; j--)
        printf("%d ", point[i][j].index);
    }
  }
  cout << endl;
  return 0;
}

### Prompt

Generate 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;
class Point {
 public:
  int x, y, index;
  Point(int xt, int yt, int i) {
    index = i;
    x = xt;
    y = yt;
  }
  Point() { x = y = index = 0; }
};
long long dist(Point p1, Point p2) {
  long long a = p1.x - p2.x;
  long long b = p1.y - p2.y;
  if (a < 0) a = -a;
  if (b < 0) b = -b;
  return (a + b);
}
struct comparex {
  bool operator()(const Point &p1, const Point &p2) { return (p1.x < p2.x); }
};
struct comparey {
  bool operator()(const Point &p1, const Point &p2) { return (p1.y < p2.y); }
};
int main() {
  int n, c = 0;
  scanf("%d", &n);
  long long total = 0;
  vector<vector<Point> > point(1000, vector<Point>(0));
  Point p[n];
  for (int i = 0; i < n; i++) {
    int x, y;
    scanf("%d %d", &x, &y);
    if (y == 1000000)
      point[999].push_back(Point(x, y, i + 1));
    else
      point[y / 1000].push_back(Point(x, y, i + 1));
  }
  for (int i = 0; i < 1000; i++)
    sort(point[i].begin(), point[i].end(), comparex());
  for (int i = 0; i < 1000; i++) {
    if (i % 2 == 0) {
      for (int j = 0; j < point[i].size(); j++) {
        p[c] = point[i][j];
        if (c > 0) total = total + dist(p[c], p[c - 1]);
        c++;
      }
    } else {
      for (int j = point[i].size() - 1; j >= 0; j--) {
        p[c] = point[i][j];
        if (c > 0) total = total + dist(p[c], p[c - 1]);
        c++;
      }
    }
  }
  if (total > 2500000000) {
    for (int i = 0; i < 1000; i++) point[i].clear();
    for (int i = 0; i < n; i++) {
      if (p[i].x == 1000000)
        point[999].push_back(p[i]);
      else
        point[p[i].x / 1000].push_back(p[i]);
    }
    for (int i = 0; i < 1000; i++)
      sort(point[i].begin(), point[i].end(), comparey());
  }
  for (int i = 0; i < 1000; i++) {
    if (i % 2 == 0) {
      for (int j = 0; j < point[i].size(); j++)
        printf("%d ", point[i][j].index);
    } else {
      for (int j = point[i].size() - 1; j >= 0; j--)
        printf("%d ", point[i][j].index);
    }
  }
  cout << endl;
  return 0;
}

```